Stricter requirements for Mentors.

[Deceptus]

Personally I'm for the latter as the demotion point, however it will need to be able to distinguish when one is intentionally leaving and internet/game related crashes that leave one unable to log back in (usually leading to removal from the party). Depending on how you look at it, both could be considered leaving an instance before completion and it's not necessarily fair to punish legit issues with a penalty.

Seriously if Dixie's idea was implemented all a mentor would have to do to circumvent the system is Alt-F4