TER white listing.  Of course that helps them to know something about you and what your screen name is, and think twice before you want to give up the anonyminity.

As far as asking goes, I don't see why not.  The worst they can do is say no.

Does being white listed help with verification?  Yes, it does help but it's up to each provider how much it helps.

Is it up to the provider you met to white list you? Yes, it is up to her.

Is it tabu to ask the provider to white list you after the date or just see if it happens? No, not tabu. It's fine to ask after the date. Might want to wait and ask by e-mail instead of while still there. Doesn't feel so much like being put on the spot that way.