If I saw it had a scratch or other defect through the bubble, then I would return it without opening it. In fact, I study them first in the shop before I purchase to make sure I get the ones with the best paint apps and box. I've left toys behind that I really wanted just because it had noticeable defects. The looks I get from staff and other shoppers is quite funny because I literally pull everything off the shelf / pegsI do put them back though.
There has been the odd occasion when these things are not noticeable through the bubble in which case I have already opened it and then went back for a refund.