I've always said the standard MO here is to gain trust then scam - look at the history of staff and treasurers.
You are bringing your own problem here but true, we had a good number of members who scammed after gaining high reputation. But that does not mean you give the same tag to everyone. People are different. We had a newbie who send back some BTC that was mistakenly sent to him. Isn't is a positive example?
Now that he has tried his scam and failed, why would he even want to stay here? Ignoring this would just empower other scammers.
There are no scam happened yet. No one is giving an open highway to scammers too.