This does not sound like a good idea to me.
I can’t see where a decent person would in good faith participate, but it sounds like a magnet for scammers.
Maybe I’ve been at this too long, but I’ve found that scammers look for vulnerable targets (new shops) and play the same game.
“I ordered a pizza here last Friday and it had wasn’t supposed to have green peppers, and when I called, I was told that I could get a free one next time” Or even better, “a full refund”.
Of course with a POS system, I can pull up last Friday’s data and kindly inform them that I cannot find any record of their order, but with their name, address, and telephone number, I’d be glad to research the matter further and get back to them.
At that point, they usually hang up, sometimes with a few choice words.
I guess I’ve been a bit jaded when I realize there are people out there who scam for a living.