Surrender at 20

Heya all,

Just wondering if anyone knows the purpose of the 20 minute timer on surrendering. Had some matches with some trolls the other day that makes me wonder why players cannot surrender before 20 minutes. I mean it makes sense to have a minimum time, don't get me wrong, I don't want it to be possible to surrender before 7 minutes (minimum time required to get a reward), but 20 minutes seems a bit high for some games.

The main reason this seems odd is that it requires 4/5 players to vote for surrender. Is it because the enemy team should be allowed to continue farming kills after completely stomping someone? If the game is 40 to 2, and only 10 minutes have passed, obviously something is wrong. It could be just about anything, but at this point is it really worth holding both teams in a match that is pretty obviously over?