Problem is the blame culture we live in. if someone trips on a rock, they dont say "damn, I tripped because I didn't look properly... this sucks, lets get to the NHS!".. rather they said "damn, I didn't see that rock... let's sue the site owner!!". So the insurance is basically there to make sure the site owner wont be sued to oblivion. Also so that police know that you're there. I hate all those regulations. There are plenty of organised games where I live, but I don't tend to go to them. I much more enjoy to set a time a few days in advance, show up, chill, have fun with friends, laugh, spend too much time in safe zone and go for a pizza afterwards.