Heh.
It's a huge expense the club would have to front. I'll say again that clubs right now can be as little as some ground in the middle of nowhere and a wooden hut. Each member has responsibility to secure their items in a gunsafe at home. Distributed security, lower concentration of value.
But you're wanting the club to have an underground vault and 24h surveillance and not explaining the benefits.
You specially mentioned people leaving expensive vehicles on the street as if them getting nicked is something that makes this all better. Besides nicking vehicles which have security flaws or lifting them onto a flatbed there's the straightforward method of personally menacing the person with the keys to get them and the more expensive the car (or pile of firearms) the better value that is.
All the club firearms in one location and you just need to threaten or assault the owner to get it all?
Securitas, which handled money for the banks who don't hold a damn thing these days, got rolled in 2006 through a depot manager and his family getting kidnapped.
All that security and in the end you just need to threaten one person to get past it all. Great.
