Server owners can give players special privileges if they donate, some of which can make them invincible. (PC, Team Fortress 2)
A lot of servers have different abilities, and it pisses me off, but ultimately their isn't much anyone can do about it.
Just get off the pay to win servers, only 12 year olds play on those anyways.
Man, I'd love to spectate that lobby. Wactching all those cheaters shoot at each other forever, highest k/d will be 0/0, lol.
But hey, that's what they deserve.