3 months is nothing compared to the cumulative amount of time these players have wasted for others (and themselves). They're getting off lucky, and the same people will just be back in 3 months to start the routine over. In the meantime, they'll probably be replaced by different offenders that don't shout what they're doing from the rooftops. A ban like this doesn't solve the issue at its core. Win-trading is still going to be prevalent, people are just going to be more discrete about it. Tossing out a ban to a few key-offenders every few months is a great way to make things seem okay.