It kind of depends on the level of the game and how good it is, the higher of both, the better the chance is that enemy team will let you pause. Of course there are jerks in every level that will unpause whenever they want.
The best time I had when I was playing vs. a 5 man stack and one of them needed to restart to fix a bug and we waited for him, and then one of our players disconnected. I was dead and saw he was just auto attacking creeps for a few seconds while enemy QoP was hitting him, so I paused and then he DC-ed.
Guess what they did? Unpaused and killed him, before the guy returned. We also had a guy suiciding and then AFK from 5 minutes in, so that was a free loss. Really annoying since these are the kind of jerks you want to win against.
"Riou...you came. Just like you promised. ...here we are ...here once again."
Some people have very limited time to play and can't afford to wait around for 5 minutes. Some people want to maximize their time playing for practice rather than try to play as many complete games as possible, so they would rather keep going and don't care if it means starting a new game 5 minutes later.
It's unreasonable to expect 9 people to consistently wait because 1 guy is having connection issues. It's nice when they do, but if they want to play on you should accept it.
I always wait and even pause if my team mates unpause if the game is tied of kinda close. If its a blow out I could care less either way. Only one time I had to hurry the game was running long and I had to catch a bus. I was the carry and they complained because there Lina was Afk for a phone call. We had the game won but I had five minutes and no matter what I had to leave.