For whatever reason, some of those had me laughing hysterically!!!! LOL So bizarre!!!
No, it wasn't a security flaw. Back in the early days, you did NOT need to have a transaction with someone to be able to leave a transaction. Also, back in those days, if someone who left you a positive was naru'd, your positive was turned into a neutral. (I have three of those). I forget when they changed the rules but it was several years ago.