Not for message board spam, unless it relates to your account somehow. IE. you spam a forum and people buy from you, then you get a high number of chargebacks or complaints. That can get you in trouble. If your complaint rate is too high (there's no specific formula for this, it's often at the discretion of Fraud) you can have your account limited, locked and/or closed. Generally if you follow their rules, and abide by their AUP (acceptable use policy), you shouldn't have any problems.
Hard to say, people are weird. It's not the advertising that will get you in trouble though. What I was trying to say is: if people file claims on their transactions with you, or do chargebacks, that is what will cause you problems. Otherwise, I don't think it matters where you advertise, but I would have to check the User Agreement (I'll let you do that )