I never buy games off of Amazon not to mention pre-ordering them, if I pre-order Tera there this is what I can expect right:
1. Money not charged until shipped?
2. Will get a code for all cbp's to be entered somewhere on the tera site after making an account there?
3. Will get the physical copy early enough for the head start?
4. Will get the option to dl the launcher/ game files right now from enmasse after making said account.
5. Can cancel pre-order if I want from Amazon.
2. Yes, when I applied my code the website told me I was eligible for all CBTs.
3. Probably not. With SWTOR head start, they sent out codes that allowed you to play in the head start, but didn't send out copies until release IIRC. However, since OBT goes straight into full release you shouldn't need the physical copy to be ready for head start?
5. Yes, any time before they enter the "shipping soon" phase. Once it has entered that phase, there's a chance it may or may not get cancelled, but they don't enter that phase until usually a day or two before.
This is all for Amazon US.
Basically, you can pre-order, get the code, and cancel your pre-order right after.