That's it! You're on the list!

I went to Best Buy for the second time this week looking for Futurama volume's 3 & 4, which were on sale for $19.99 a season (better than used). I went to a different Best Buy earlier in the week, and they were out. So I went to a different one today and - ta-da! - they were in stock. They still had the sale price posted, too. But when I went to the register, it came up as $27.99 a piece. I caught it right away and showed the cashier where the sale price was displayed. He then removed the sale price for all four volumes (even though I was only buying the last two volumes) and took them back to the register where he rang up the sale price. He then had me fill out a form with my name, address, phone number, and signature that he said was necessary since he put in a different price from what was in the computer. So that leaves me with two questions: One, did he put the sale prices back, or was I the last person with any chance of getting the sale price because he removed the displays and therefore any evidence that they were on sale? Two, why did they need my information in order to change the price from the one in the computer to the one they were advertising? Will I be put on some kind of list of customers who watch the register to make sure the price rings true? If I do this often enough, will they block my Reward Zone account and refuse to mail me coupons anymore? Will they charge my credit card full price if they find out they were suppose to have pulled down the sale signs sooner? Um, I think that's more than two questions. Anyway, two seasons for the price of one (after coupon)! Hooray!