I'm aware that chocolate is definitely one of the no-nos for a cat to have, but the question is whether or not a cat would really even invest much effort into eating chocolate in the first place? I know for dogs, absolutely they will, especially Reeces Pieces due to the peanut smell.
I have kids coming over, and was told they LOVE chocolate, so I put out various little wrapped chocolate treats like Ferrero Rocher, Raffaello, Reeces Pieces, Mini-snickers, etc.
I'll keep these away while the kids are gone, but when they are here it would be difficult to leave it out and keep an eye on the cats 24x7.
Think they'd even bother with it?