FAA Part 3 of 14 CFR Part 48, Registration and Marking Requirements for Small Unmanned Aircraft doesn’t mention an ID, but you are supposed to show a certificate of registration when asked by any law enforcement officer:
“Federal law requires...
I use a 6-meter, $99 USD telescoping flag pole and also a 7-meter $40 US Dtelescoping painter’s pole.
https://www.harborfreight.com/20-ft-telescoping-flag-pole-kit-64344.html...
I’ve always given references to verifiable receipts and serial numbers on my high price sales, and even put a newspaper with the date in the photos- but there are too many easy ways of spoofing photos to make them look original these days.
Paypal doesn't have your back like they used to, they use AI now to solve disputes and it hallucinates all the time. I had an aliexpress seller bait and switch an order, and paypal utterly failed and wouldn't do the right thing... Don't trust...