Only happen to me at banquet setting like a formal wedding dinners or a company holiday party. Catering seemingly has different rules that restaurants. I understand they are just trying to make room for the next course and the are on a time table, but if I am not done, the plate stays. So I only find it rude if they take it without asking (unless I have made an obvious dirty dish pile at the end of the table), or in the case a banquets are active pressuring you to hurry up.
And yes, please drop of the check ASAP if I have signaled I'm done ordering. I hate waiting 20 minutes after finished dining to leave. If I change my mind, you can add the extra drink or dessert.
I've worked in catering for banquets in a hotel. For the one I worked at at least, the initial set up is before anybody comes in, the room is split into two. Waiters generally take two or three tables. The palces are set such that you have cutlery for starter, soup, main course, desert, and tea/cofee (so a knife and fork for starter, a spoon, fork, and bread knife for soup, a fork and meat knife [a steak knife is initially there, if somebody is having fish then while ordering we swap knives], a spoon for desert, and a spoon for tea/coffee). You work your way in, from the outside, each course. After we take orders (choice between main courses, and a vegetarian option which isn't advertised), everybody has a chance to talk, order drinks, go to the bathroom, etc. After a short gap you're called into wherever the chefs are putting things onto the plate, and for your side of the room, there are three stacks of plates. Food is placed on the top plate of each stack, and then you carry them in, starting at the top table (where the bride and groom are, or people of msot importance) and we work ourway to the opposite side of the room (so you come in, collect three, place three down starting from the top of the room [for the main course you just look at what type of knife they have as that indicates their choice], come back, line up, and take three more again). After the first course of meals are brought in, you wait around at the side; you're not meant to go over to each table and ask the people at it if they need anything because not only might you be interrupting photos or conversations, but you don't want to be sent off on a bunch of tasks when you may have to clear the table or do another job, you wait to be called by anybody who wants you. In the mean time, if your water jugs on tables are empty, you fill them up.
The host of the event wanders around the room talking to guests and ensuring everybody's enjoying themselves, but he's also checking to see what progress everybody is making on their food, and keeping track of the time (while you're having a course, the next course is being made in the kitchen, as soon as it's fresh and done, it gets put on plates and served, the chefs don't take kindly to delays as it impacts the customer's appreciation of the food, so time management is extremely important). Once most people are finished, he signals to everybody to start collecting your table's plates. If somebody is not yet done, you leave them with the plate for the moment, but you need to collect everything related to that course (so at starters, you take up the cutlery, and the plate being used; after the soup, you take up butter from the table, cutlery that should have been used with the soup, remaining bread, bread knives, side plates; after the main course, you take up salt and pepper, plates, cutlery, the plates that the water jugs were on, the table number and associated stand, and the menus; after desert you take everything else off and clean it).
At this point, there's generally only a few minutes before the next course is on the way. The general rule is, unless somebody is visibly eating their meal, you assume they're finish and move on, you don't have time to ask twenty-four to thirty six people if everybody is finished their meal, especially when most people are engaged in conversation and don't acknowledge your existence (a lot of people are drunk). Anybody who is still eating at this point is an exceptionally slow eater, because most people have finished for a short length of time, hence everything being called. You clear everything else and if, by the time everything else is done, somebody still hasn't eating you tell the person hosting the event. They'll talk to them for awhile and ask if everything is okay and if they'd still like to continue their meal. If they do, you just carry on and ignore them. You bring out their next meal with everybody else's, and the process continues until after the main course (during the main course, you sometimes get deligated jobs, such as to bring extra vegetables around to each table and see who wants them; if you get lucky you fill water jugs) when most speeches are made. You have to put away all of what has been cleaned (that which you brought in ealier; they might be used in another banquet on in another room, or the hotel restaurant), and do any other jobs while the speeches go on. As soon as they're done, you bring out deserts, When tea/coffee is done, you empty everybody's wine into the water jugs (unless somebody explicitly protests, you don't ask, you only don't if you are interrupted), and clear everything. You then quickly clean the room (hoover, change linen on tables, move the tables, set things up or remove if necessary), the band sets up (why timing is so important in general too; the bad is hired for a certain length and you better be ready by the time they are booked) and people are brought back in to dance/order drinks if they want, and your job is done after you do the few remaining cleaning tasks (a skeleton crew stays on). Time management is too important for the entire thing to be delayed by one or two slow eaters. If you feel like you're being pressured, it's because you are; the managers really cannot afford to have the entire thing delayed. When you need to have two/three hundred people at their seats, orders taken, four/five courses given to everybody with a delay between each course (so people can chat/relax/go to the bathroom), and the room needs to be cleared, cleaned, and have the layout changed for a band and the guests, you cannot feasibly delay things for two or three people, and small delays have a knock-on effect.
I hope that provides greater clarification to how (some) banquets are catered. EDIT: Regarding a dirty plate pile, for us anyway, that wouldn't have made a difference. We put all knives in the same direction on a plate, and put all forks perpendicular to them above them to hold them down. You then hold that plate in your hand, and pile the rest of the plates on top of the same hand to carry them. You work in one direction around the table, regardless of what the guests have done, because you can't afford to keep on encircling the table or going around it at random when you've one or two more to go to.
