Ask HN: How to implement a national "do not email" list

Follow-up marketing emails have become obnoxious. Every point of sale (especially brick and mortar) sends a marketing follow up, and it’s not clear how to opt out during the transaction.

Restaurants, bars, parking apps, ticketing apps , first parties, third parties are all “spamming” with promos, surveys.

Since cash is not an option, a single night on the town results in 6-12 emails the following day.

Since no one is addressing the network affects, nor tracking the violations to the CAN-SPAM act

my question for HN community is:

How would you create a national do-not-email list to opt out of automatic marketing enrollment during the point of sale.