Also more importantly I think it would be neat to be able to reply to a invisible GMs within a small time frame after they tell'd us.
It would go something like this if you were playing as Thedude talking to "invisible" GM Norris:
tell Thedude I like tacos!
[From Norris ::3 minutes left to reply::]: I like tacos!
re Norris Yeah man THEY ROCK!
[To Norris ]: Yeah man THEY ROCK!