Down here we were required to get police clearance of the weapons, and any loaner guns. I believe we initially had to contact the local chief of police just to get someone to come and clear the weapons. In the end, a police cruiser came down to make sure all the weapons were not real-arms replicas. We had to do this for two reasons:
First being that the reciever on all weapons was painted over, didn't matter of the colour
Second being that we always removed the craptastic orange flash-hider or painted the half-decent flash-hiders.
We were also instructed to keep possession of our "loaner" guns. They're just crappy little M4's from Wal-Mart that we purchased so that new players that joined us could experience the game without dumping 200-300$ on a weapon. By possesson of, they meant that we must have the weapons when they are not active. Even on the way to the match, we had to have them, they couldn't be in someone else's vehicle, even if that vehicle was directly in front/behind us (You should have seen the old lady's face when she saw 4 guys in camo with about 6 M4,s 2 AK47s, a L96 and a SiG552 in one car
I don't know if all this was due to the fact that we play on someone elses property (We go 20 minutes or so outside the city to my brother's friend's uncle's place, because they own acres of forest and we play there) and not a real facility designated towards the sport, or if it's just strict law and whatnot.