Here is what I would do:
- come online and see a bunch of zaps from a bunch of weird mints I don't know and think "huh, cool"
- press a withdraw button that does the following: make a single multi-nut payment from any mint you don't trust, if the received balance exceeds say 10k sats, to your trusted mint and cleanse the untrusted balances.
The nice thing about receiving tips is that there is no expectation. Either you get something, or someone is trying to mess with you and it's easy to hide the second part from the user.