Is it possible to add to the Block mechanic the idea that if one of my friends has blocked you, that fact is obvious (your name appears in red, or with a badge or something) - and that the more of my friends who have blocked you, the more "foe-like" you become?
I keep thinking about how to deal with certain kind of griefing, in the recognition that it impossible to completely correct for it. Some sort of social mechanic seems a good tack for Glitch, and being marked for your bad actions would lead to consequences for them.
I would expect that many Glitchen might think think twice about being generous to someone that 5 of their friends have blocked, and that might be an effective curb in itself.