For a variety of reasons, I don't want to call shenanigans on anything Kintaro is saying outright, but I will say these few things:
-It is possible to obtain a refund for a digital copy purchased anywhere through NCSoft (not ArenaNet) customer support if you haven't applied/registered your serial key. I know this because someone did it successfully after accidentally pre-purchasing twice. This is exactly how it should work because if they didn't use the key they haven't done anything as a result of the purchase that makes any impact and are of course entitled to their money back. This should be the case to anyone who pre-purchases and did not register their beta code.
-An employee at my local GameStop clearly distinguished between pre-orders (in which a customer puts down an amount of money they choose, untaxed, and a physical copy of the game is reserved for them in the store) and prepurchases (in which the customer pays the full amount including tax, and is given a code for beta access). I asked if I could put down $10 and still get a key (hoping he was uninformed enough to let me do so) and he immediately said no and that he had to enter the transaction for a full pre-purchase separately.
-If GameStop refunds a customer in full for a pre-purchase, I have to imagine that that particular GameStop does not call up NCSoft or ArenaNet to tell them to invalidate the associated beta key. I'd love to be proven wrong about this, but it doesn't seem likely. This is very, very bad. It means not only that someone could intentionally pre-purchase, register the key for a beta weekend, play through the weekend and then go back to get a refund (as Kintaro's four customers did), but also that they could continue playing in any future beta weekends unrestricted, despite having put no money down and not even intending to get the full game, which could potentially even skew ArenaNet's numbers for allocation and server distribution if a significant number of people do it.
-You cannot get a refund on an activated code that was purchased digitally; this would be equivalent to buying and opening a retail game from Gamestop and trying to return it for a full refund. For all intents and purposes, pre-purchasers that got the game this way do own the product already, and our accounts, the installed client, and so forth will remain the same at launch, we simply don't have access to the servers unlocked. Retailers of physical copies are handling this differently and I don't blame either side for requiring the customer to come back into the store to get a second code at launch.
And now I guess I would like to address Kintaro regarding the "lol is prepurchase for the full game or not" nonsense.
Yes, you are pre-purchasing the full retail game for $60. None of the extra stuff you get (hero's band, headstart access, or beta weekend access) are part of the cost of that $60. Anyone looking at it that way needs to seriously adjust their expectations, quite likely in all areas of their lives, not just waiting for videogame releases.
Those bonuses you are given for prepurchasing are given because you bought the game early. That's all there is to it. Essentially you could even consider them free- if you were going to purchase the game when it came out, you're being rewarded for putting the money down now instead. If you weren't going to purchase the game when it came out, or you weren't sure you wanted it, why would you purchase it in advance?
Anyway, again, I'm not saying Kintaro is lying about the 4 people that came in and got refunds. In summary I'm just saying it's a bad idea if retailers are doing this and opens things up to a lot of potential abuse.