Our hobby involves wandering around Cambridge and environs, armed to the teeth, with realistic looking weaponry.
(God only knows how the Assassins cope with this, but that's a different story.)
You may, at some point, be approached by members of Cambridge constabulary, asking wtf you're doing. I have had this while standing at a bus-stop in full kit. Leo had them knock on his door after being reported by his neighbours. Anyone walking through town carrying a big sword may get this.
I feel it worth mentioning at this point that people are getting lax about the obvious precautions like always carrying weapons in bags (or even wrapped in bin liners). It's worth being careful when you can. --Pufferfish
In the event of being questioned by the police:
3)Offer them the weaponry to examine. Point out that it is mainly made out of foam, or is otherwise harmless.
4)Do not try to explain LARPing to them, unless they ask.
5)Say the weapons are theatrical props, or that they are for a game you are playing as part of a Cambridge Uni student society. This is perfectly true.
6)Mention Treasure Trap by name if asked.
7)Volunteer that we are normally playing a room somewhere, or well away from anyone else, and are very careful to avoid injuring each other, and especially members of the public.
8)Remember rule 1.
And then, come and tell us about it.
As someone who has lived around several coppers I feel it is worth pointing out that contray to the media most of them are decent ordinary people who are not out to lock you up (if nothing else it causes a WORLD of paperwork) and that if you keep calm and remain polite they are likley to relax and ask you friendly questions about LARP once they have determined that you are not a crazy with a real sword (and in one case have radioed in for "a fag break" followed by "can we have a go?").
It's the bit before that where the problems come, because don't forget: they may have been specifically called out with the information that you are carrying a deadly weapon around in public, and are going to act under that information.
The unoffical policeman motto, enforced by every copper I have ever spoken to is: "if they are being difficult, then let them have it". So if you cause them trouble (I can't see anyone actually picking a fight, but by this I mean refusing to give information, generally not co-operating), they will cause it right back, and having had my dad detail a few of the things he used to do, the quantities of pain and inconvenience they can cause you if you make it worth their while are nearly limitless. Show you are a happy honest citizen and help them do their job and things will go much easier. --Drac