$5. PayPal did it and Coinbase did it. That's 17k sats.
6000 users per btc.
Those were KYCd users to reduce abuse. Keeping KYC out of the equation means limited zapping or some proof of work. We could send satograms giving everyone with a lud16 lightning address identity set in their profile sats periodically.
We could pay for them to delete accounts! Proof of Exodus.