Bachelorette Party etiquette, sorta... I'm the arranger for my friend's non-traditional bachelorette party. The bride wanted to go to a restaurant for food and drink and then to private room karaoke. (No gifts, no veils, no phalli.) It's all arranged and the RSVPs are in.→[More:]

My concern is about costs, since tradition dictates (and the bride expects) that everyone pays for themselves, plus covers the bride. Do I need to "warn" people about the estimated costs? I'm happy to cover the bride as sort of a bonus wedding gift, but I'm worried about the invitees either leaving the karaoke without paying or underpaying because they don't know the costs, and me getting stuck with the balance. Box karaoke is $8 per person per hour, plus people will be ordering drinks from the in-house bar, and the whole tab will require tax and tip. (I reserved a room for 15, for three hours.) How do I make sure, in a graceful etiquetteful way, that everyone ponies up?