As promised, here's a play-by-play of my post-HTS.com order goings-on (a lot of this is in retrospect, since I was out of town for a few days).
Monday Night: I place the order and it goes through. My account is created and all is well.
Tuesday Morning: Before leaving for a trip, I notice that the receipt I printed out is missing part of my address and I call the fine people at HTS.com on their 800 number to let them know of the mistake (the part of my address that was missing from the receipt and my order on the site was still present in the actual account section). The woman I spoke to said (and I'm not making this up) that they could not access any of the orders from the previous night until Wednesday and therefore I would need to call back then to straighten it out. Try as I might, I couldn't think of a legitimate reason to ask why they couldn't access their own information, so I just decided I would call back the following day.
Tuesday Afternoon: Hasbro placed a temporary authorization on the card I used for the full price of the Battle Arena I ordered the previous night. How they did this without access to the order information is beyond me, although I'm sure that voodoo and my third grade spelling teacher are involved.
Also, Hasbro sends me the order confirmation email (again, how they did this without having access to any of it is something I don't understand).
Wednesday Morning: I call HTS.com's 800 number again and the woman who I speak to is very helpful and is able to make the necessary addition to the address on file for that order, which HTS.com is now apparently able to access. I am happy, since this means that my order can be shipped out.
Thursday Afternoon (10 minutes ago): I check my order status at HTS.com. The Battle Arena, listed as "In Stock-Ships Within 24 Hours" when I ordered it and when I double-checked the day afterwards, is now scheduled to ship on May 12th. Yep, over a week later (I guess the "usually ships" comment is put there so they can say, "Oops, we're sorry" but then again, how can they even judge when something "usually" ships until they've been open a few weeks and have actually shipped anything at all?).
So now I'm playing the waiting game on two fronts: the first is to see whether or not the Battle Arena will ship earlier than the May 12th (in other words, closer to what they originally stated it would), and the second to see if they actually charge my card before they ship the toy.
Further updates will come as this story develops. And now, back to your regularly scheduled programming.