Wikipedia excerpt, Interesting definitions
http://en.wikipedia.org/wiki/Cutting_(in_line)
"Covert cutting
In lieu of following the procedure mentioned above, some will cut in line by joining up with family members or friends already standing in line. This action is usually more acceptable, but can still be considered "cutting". Many times, this action is purely out of convenience, when one member of the group "saves a place" for the other members, especially when the wait is lengthy. However, this is not always the case. It is more acceptable when the two people are simply together to conduct one transaction, however if both people plan to conduct one transaction each, it is particularly disrespectful (especially in queues with slow cycle times due to high individual transaction times)."
This definition fits some of what has been discussed in this thread, but not all of it.
First, lets remember that wikipedia carries zero authority anywhere in the world. So this definition doesn't necessarily mean anything and there's certainly no reason to believe that Disney has accepted or adopted this definition.
This definition would seem to apply to those families that choose send one or more people for fastpasses while the rest of the family gets in line for another attraction, with the intention of letting the fastpass runners cut the rest of the line to join them.
This definition doesn't seem to apply to somebody who's in line who has to leave to go to the bathroom, because it doesn't say anything about somebody who left the line, then returned.

..... anyone hear what I'm thinking?..... 
