Corrected entry: In the half-room, Wonka angrily tells Charlie and Grandpa that there is no lifetime supply of chocolate due to stealing fizzy-lifting drinks and touching the fan which needs to be 'washed and sterilized.' But how did Wonka actually KNOW that Charlie and Grandpa did the above, since they were alone at all times and there were no Oompa-Loompas or CCTV cameras watching them? Also, when Charlie and Grandpa rejoin Wonka and the others, Wonka is carrying on without any suspicion whatsoever and he doesn't question them till they get to the half-room.
Chanteuse66
13th Jan 2008
Correction: It's not hard to imagine Wonka having a security system that would have let him know what happened with the fizzy lifting drinks - it wouldn't necessarily be visible to anyone. He never mentioned it to Charlie because he intended to use the incident as a sort of "final exam" to test Charlie's reaction and see if he was worthy to take over the factory.
Chanteuse66