You just had dinner with friends and one person is paying for everyone with everyone else paying them back. Feel free to frame your response with different threat models in mind. (Please state the threat model as part of your answer.) Also, assume that there is someone in the group you have never met before.

The obvious solution is to let someone else pay the bill and pay them your share in cash. Let's assume you're dealing with a group who strictly avoids carrying cash on hand.

Some tools that I'm aware of that can accommodate for group payments:

1. Beem It (Requires agreement to their privacy policy. Do you trust this app? The apps don't seem overly invasive. The Android app has a fair number of trackers which some people may not like.)
2. PayID (I've been reading that there are privacy concerns in PayID related to reverse look ups. Not sure how relevant they still are.)
3. Cryptocurrencies like Monero (for the purpose of the question we should assume that most people are illiterate in this area)

Are there any other tools I've overlooked? Please share specific strategies for each tool as well. E.g. you use a custom domain with such and such for PayID so that the payers won't know anything.

This topic is an open discussion that I wanted to start just to see if there was anything I hadn't thought of.