Seems reasonable to me. For the silent auctions I've attended, barbers contribute haircuts, masseuses contribute massages, dentists contribute teeth whitening.

Seems reasonable to me. For the silent auctions I've attended, barbers contribute haircuts, masseuses contribute massages, dentists contribute teeth whitening. PG's profession is advising startups, so that's what he put up for bid. If you won the teeth whitening but wanted to engage the dentist in a conversation about sports or society or the state of the dental profession, he'd probably go for it, but it's not odd that he offered his expertise to the fundraiser.