2) How much checking is involved? I'm asking because I can see there being the potential for abuse if you want to get someone banned you could point a conversation in PMs a certain way. Would be difficult, but not impossible if the person trying to get someone else banned has a few alts.
I guess logically, a user will be banned if he is the one who goes first with DMs to other members with kind of spam, scam, incentivized contents.
If you want attack someone and use 100 accounts to DM that one, it does not make any sense and the receiver won't be banned. You won't be banned because you're answering others.
Who goes first is most important if the procedure is solid.
I was thinking more along the lines of I send you something, you say 'not interested contact this person' who is an alt of yours.
I send to that alt more or less blind and then you report it. 1st hit / report no big deal, and I never know about it.
Then you wait for the next message from me to one of your alts or even your main account and report that.
It's a lot of work and planning to just screw with someone, but if you don't think people will do it then you have a better opinion of humanity then I do.
There are a couple of other scenarios that could also mess with people. I don't think it's a big deal, since we probably would have heard about it happening to people, but since it's out there it might be worth a discussion.
-Dave