One of the weirdest charges I've encountered this year was on the Veendam.
Lovely ship, lovely cruise, but they charged a deposit of $10 for the key to go out on the deck for the lanai cabins. This is the key that will let you back in. Well, ok. Didn't bother me until I dropped it at the desk with about 50 people waiting in line for their complaints or whatever and I never got credited for the $10. I didn't go to the desk the next day to have it removed since there was such a long line.
It was petty, though, of the cruiseline to charge a deposit for the key. I could have asked my stateroom attendant to return it for me but he was busy enough.