When you add a user to your blacklist, how does that afect any torunaments that you may be in together? now or in the future? If the computer draws a mathc between you and your blacklisted opponent do you still play the game or is the structure changed to avoid it ?
You can't change the structure. You need to consider what happens if someone just blacklists people that he loses to. If you play in a tournament, the blacklist should be ignored.
As I understood it, the blacklist effects only 'messages' not games... so you can play against a blacklisted person, but he can't talk to you... but since I'm not sure I can't write the FAQ. So you can play in (and maybe even out of) tournaments against ignored players.