I also got a PM from @nakamura12 yesterday. But the amount is different, he sent me a PM regarding $10, not $5.
That's exactly what the Report button is for. I think it was hilariousandco who said it leads to a ban if several reports come in. It's basically spamming for money, and if he'd be asking many people for loans, it's an exit scam waiting to happen.
Yea, it's looking shady. I wish no other person will claim he was asked for such a loan by Nakamura12. If it's more than 2, it's a clear Pm money spam.