If they are getting a manicure of any sort, I'd say at least 90% will be upset if polish isn't offered. I know I would be! Be prepared to do it, and for those that don't want polish, offer a shape and cuticle prep, plus a hand massage. That way everyone is happy!
I've often done 15 minute "mini manicures" at local school events and fundraisers - there is always a queue and it's very popular. I've done nails in gymnasiums, classrooms, school fields, shopping malls... they all want polish. I can do a french with an additional 5 minutes, and this is very popular as people usually can't do a nice french job on themselves.
But there's lots of ways to help polish dry faster! Use a fast dry top coat. Get some Rapi-Dry spray (OPI) or one of the quick-dry drops that are on the market (these are a great thing to have in your kit anyway, so don't feel like you have to buy it just for the party). Because these ladies are at a pamper party, once you are done with them, they will have a chance to sit down with a glass of wine, and are much less likely to wreck their polish than if they have to go function in the "real world" (going back to work, chasing children, getting into their car, etc).
This is what I normally do:
- quick shape (work very fast for this part!)
- base coat
- 2 thin coats of polish - because you are working faster, you don't want them to be too thick or they will bubble
- top coat (use a quick dry one)
- I do a quick tidy of any messy edges with a bit of polish remover on a cotton bud
- spray of OPI Rapid Dry
- off they go!!
If you are feeling really time pressured, you could drop the base coat, but I still think it's needed to protect the nail and you are still putting your name and your work out there - you don't want to offer a crummy service and have people think that you don't do a thorough job. And they will be realists as well for the most part - they know that you only have 15 minutes so it's not like it can be the exact same service as one of your luxury manicures.
******* Oh, also - I just remembered.... BIG TIME SAVING TIP! ******
Make sure that their existing polish is off before they sit down with you! If you have an assistant, get them to take it off first, or if you have to, leave the bottle of remover and some cotton wipes out and ask people to please remove their own while they wait for you.
I remember one lady coming to me for a mini-manicure (she wanted a french), but her cheap Rimmel varnish took a good ten minutes to get off!
I have a young girl who sometimes helps me with these events (she's my babysitter, but she loves nails and would like to train when she's older) - she's very helpful when there is a LOT of people and there's a real time pressure. She organises the ladies (puts names on the queue list, helps answer questions, etc), fetches me things, and helps take off polish. She also handles payments, which gives me precious minutes to work. Do you have anyone that can give you a hand?