Referral cheating

I see people finishing the referral task with accounts that may have only a one letter difference to the account that was refered. What are the rules on this? Should I report the person who is doing it when I see it?

i would contact support cuz it arent new players

i would contact support cuz it arent new players

It arent new players?

omg then they... english is my 2nd language

Just making sure I don't want any confusion lolz