[TheThinkTank] On-site Bike Tuneups, do you charge?

I know Community Cycles isn't the only bike organization out there who gets these (often uber last minute) requests to "just send over a bike mechanic to do some repairs at our event...". We've done this before, but as the weather gets warmer, we're seeing more requests.

How do you handle these requests? Do you charge the event hosts? The cyclists?

Thanks, hope the traffic on thinktank has been slow cause we're all super busy!!!

josh.