Out of interest, I once abandoned a Futsal game. A player turned and raised his fist to me after I sent him off (That was in response to him telling me to f*** off, after I cautioned him when he kicked the ball away a moment before a female opponent was about to pick it up. I found that concerning enough!!). I wasn't too shaken up to continue, and there were no other signs of trouble from anybody before then; it was quite out of the blue. So a good candidate for continuing, but I figured that raising the fist is a definite threat against my safety, so even if he was removed that's too far over the line, hence abandonment.
What was interesting is what occurred after. For one, his captain came over later and made a few comments, unfair about punishing the team, etc. I was a bit concerned about his response there, to be honest. But okay.
So, the next week I (stupidly, perhaps) accepted an appointment to the same team. Another player told me where to go, so I showed him where to go. The entire team began abusing me and walked off - and I mean, extreme level of swearing/abuse from the whole team, which continued on for some time while I was talking things over with the other referee. I left the court, and a little while later was talking to a player on the next court when one of the idiots stuck his head in the door and continued screaming abuse at me for a few minutes.
The response from the team and the utter lack of concern or responsibility from the captain over the raising of the fist tells me, in hindsight, that the entire team are a bunch of thungs and that any one of them was more than capable of punching me at any moment without any warning.
At the time of the first abandonment there was no hint of ongoing threat to my safety, and I wasn't too shaken up to continue - but I abandoned anyway. On principle, if you will. It was only later events that really showed just how right I was to make that decision.
Nothing other than food for thought. One of the reasons why I stopped refereeing Futsal really.