I agree, check them out, make sure they are charged and ready to go. Even if they notice that the box has been opened, will they really care if the device is all set up and ready to play with?
Gave hubby a Galaxy Player last year, and while I didn't set up a Google account for him, otherwise it was ready to use. Screen protector installed, memory card installed, charged up, TPU gel case on. He really appreciated being able to just PLAY with his new gadget without any fuss!