One of the problems in the "Leroy Jenkins" situation - as it applies to LoL - is that sometimes players act without thinking - particularly in solo/duo que. That is, there is the no pausing for second thought about the situation. Quite often, I've seen a player doing a preventative measure such as you might see when a Rakan does his W followed by his E, or Alistar's head-butt, but the rest of the teammates read the situation as "full on engage - don't spare the horses".
On the other hand, you do get the "constructive inting" situation caused by the "Leroys" - where a player decides that his game has gone downhill and he wants the game over with - as I saw a Fizz do yesterday. Sure, he finished with a nearly respectable KDA compared to his teammates - but that's not exactly the story. The rest of his teammates were playing catch up because that same player had fed the jungler and midlaner in the first 10 minutes - which led to successful ganks on the top and bottom lanes by the opposing team. I then saw him initiate teamfight after teamfight getting his team further and further behind. This continued until his initial request for a surrender was finally honored by his teammates. He was able to brag about his KDA at the end but he made his teammates life an absolute misery.