silly question

That's tricky! I have wondered this but about drink stirrers. My thought was that I'd like everyone to get at least one, but that every drink would not use one (same goes with straws I think)... I also figured I would want it just for CH.... and some people may have more than one drink with one... so I guessed I would get about double the number of guests, just to ensure everyone would get at least one! Just my figuring though.
HTH

I would say double the amount of people.
They don't have to last all night since the RH will supply regular ones.