I would say it depends on what the state of the game is, if someone does it from minute 1, yeah sure it's just being afk
But i have to admit i sometimes i do it in some situation
Countless times in normal do i find myself 15 minutes in with the team being globally 3/15 or something, with all but our inib turret gone and 4 vs 5 cause somebody has already ragequit.
But because it's still early they cannot necessarilly dive innib turret (or maybe they don't have the comp), more often than not they aren't very good themself so they still play 1-2-1 with the jungler farming like a beast both jungle, so the game can stall in that state for 10-15 minute provided we have some kind of waveclear.
Since we are not at the 20min mark we cannot surrend but even if we are past it there is always an assasin that is 6/7 and can go 1for1 suiciding for the support and the kid gets a kick out of it so he will not surrend ==> I'm hostage of a kid who like killing supports, and afk and some feeders (and i don't say i don't sometimes share some responsabilities in the loosing situation we are in).
In this particular case i very often do run around the fountain waiting for them to finish, cause if i waveclear i just make this painfull game last longer