I believe the underlying cause here is the PMerbabies that have become quite prevalent, who seem to believe that it is their divinely given right to abuse whomever they feel like, for the unpardonable sin of:
a) winning
b) not playing the game the way PMerbaby thinks it should be played
c) because they feel like it
d) any combination of A and B and C
These guys ARE a problem. The number of such contacts are up from 0 to 3 to 10 per game session. As Vort says, they, the undesirable element are negatively affecting the game experience of the people who are playing and minding their own business. They make the experience negative enough to seriously consider leaving for game experiences that don't require that level of pandering.
It is of course up to HTC, but I believe the smart business move is to make it clear that harassers don't belong here, its not a desirable behavior, and you do it at your own risk. To that end I think there is an easy solution:
1. PMerbaby contacts player.
2. Player says, "I don't want you to contact me."
3. Any repeated contact is reportable and action should be taken.