I know we discussed a similar topic many years ago on the forum, but I was recently asked this question again and it seemed like a good idea to do a re-poll, since we have some new active members.
Situation 1:
Pre-flop. Everyone folds around to the button. Dead small blind. Before the button has had a chance to act, the dealer -- acting very quickly -- pushes the pot to the BB, and grabs the BB's cards (presumably unprotected) and puts them in the muck. Button says "WAIT!" and still has cards, but it's too late.
Situation 2:
Same as above, but BB's cards are protected, and released only after the dealer pushes him the pot, in exchange. Button says "WAIT!" and still has cards, but it's too late.
Situation 3:
Same as one of the above situations, but SB has folded (OOT) in the interim. Button says "WAIT!" and still has cards, but it's too late.
In all cases, the dealer admits he was going too fast and didn't see the button's cards.