Feb 11th 2010 11:50AM It cares that the gem is right, not that it's epic. The only item quality requirement for gems is that epic gear should have at least blue quality gems, which isn't unrealistic especially at this point where blue gems shouldn't be that much (10-30g more) than greens.
Feb 11th 2010 11:45AM It's all opt-in, you can't sync data without first initiating it or somebody else initiating it with you, and it's sent over whisper channels in that case so raid/guild won't see the majority of it.
When you're in combat, the mod is pretty much disabled.
Feb 11th 2010 11:31AM Make sure you still have performance issues without any other addons enabled. If you still have issues then let me know on Curse or WoWInterface and I'll look into it more.
Feb 11th 2010 11:29AM You can only sync notes with people on your trusted list (Guild members/Friends). If you can't trust your guild members you can disable that. People can't really abuse the notes system to leave fake information, unless again, you can't trust the people you're in a guild with.