Could you possibly display the persons gamertag in the quick info box that pops up? Its pretty tedious having to go each members profile information to find out what their gamertag is. It would really help with customs and inviting people quickly.
When you're looking at an event, control-clicking on any RSVPd name will open a new window that sends a message directly to their account (also, hovering over their name). But yeah, I can look into that anyway