For me it depends. If they're chill teams that are prepared to split up at times, or aren't great at the game and play for fun then it's fine, but when it's a team consisting of players perfectly capable of winning by themselves who never leave each others' side and team just to give themselves the best chance of winning possible and tryhard anyone with good stats to eliminate them and act cocky in chat then it's not okay.
Prime example of this is
HEAVY1k and JELEw who chased me for over 5 minutes on SG Highway yesterday when I was undergeared, preventing me from taking a route. They eventually gave up on me to take refill while I took my route and still didn't get a rod or boots. They on the other hand had a diamond chestplate and a seemingly endless supply of golden apples. They split up to find me once they were done with refill, and I completely wrecked one of them (not intended as cocky, just what happened) only for him to run to his teammate on what must have been less than 2 hearts. They gave up on me again and killed the other guy to take it to deathmatch. Of course they hardcore teamed me in deathmatch and won, with me getting them down to what must have been around 2 hearts each despite my lack of boots, rod and iron sword to their pair of diamond swords (again not trying to be cocky). Upon killing me they both type 'gg 2ez' in chat. I was more gobsmacked than mad- these are two players with ~15% ratios who know more or less what they're doing but feel the need to deny everyone else a fair game just to beef up their stats. Pathetic.
