I’m using a weird combination of things that is kind of difficult to wrap my head around. I’m using a bind that sends a closure to a procedure, so it’s a lot of variable juggling. Since it requires two players, it’s hard for me to test. 🙁 But I’m looking into these issues.
 I simplified some stuff. Hopefully it fixes it. Your report hints that there might be more issues, but I can’t be sure. I’d have to get actual examples. Like, when you say incorrect people were teleported, you mean of the two people, right? (and not someone else who didn’t type in a command) Timing out properly unbinds the /accept command (I tested it) so I doubt that has anything to do with this. An offline exception will occur if the other player is offline during an /accept command. I could put my own error there, but an offline exception is informative.
[edit #2] I tracked down another issue with some help. It should be a whole lot less buggy now.