There was similar offer for prepaid MC a few weeks ago. I was surprised to find they’d been removed from the stores in my state. We’ve never been able to purchase prepaid Amex but MC wasn’t a problem. Maybe the MC got pulled because of the theft issues.
I saw plenty of Visa’s so I’ll be getting those for 5% on Chase Ink.
Limit 1 per customer but no Rewards card needed since no Rewards earned for gc purchases so its up to the cashier to enforce the limit.