Good one! Thanks Spunk.
Yes, it can be embarrassing to ask, and the "other" pilot/examiner/whomever has put you in a difficult position if you feel you have to. I always try to offer in advance my license, and summary of my pilot log, before I fly someone's plane. Generally the offer is not taken up. In either case, there are no hard feelings, and even if the "no thanks" has to turn into a "may I please...", the ice is already broken for everyone.
It would be courteous if all new [to the aircraft/operation] pilots offered, instead of causing someone to have to ask....