Anyway, I was auto-spamming for about 3 hours straight, getting the usual shit from people "I'm gonna report you" blah blah. Everything was fine... PSP was spamming on it's own, fun fun.
After about 3 hours I decide to log out. I attempt to log back in a few minutes later and I received a ban message.
Bans are for R:R ONLY they don't ban your PSN from other things such as PS3.
I doubt they have any sort of detection system though, probably just caught by a mod/admin or through reports. Otherwise I'd of been banned long ago.
EDIT: On top of, or instead of your PSN being banned, you may get your PSP banned. It won't say you're banned but you'll get a connection error when trying to log in.