But the steps people take to get a discount... He could probably just straihgt ask for a discount and get it anyway without making a new registration.
Using different emails or addresses or different cards is not illegal
Case in point. ChatGPT will not accept any masked email from fastmail.
I tried multiple traditional domains. No luck. The error was something to the effect "try later, too much traffic" something or other. (Hiding behind public perception, slick). This went on for days.
One day, after the 20th try...on the next second, I finally relented and used my google workplace email... (which ironically enough is not very liked , particularly by banks, since its not a traditional dot com domain). That worked immediately.