That is exactly right.
Break-in happens, someone reports, discussion heats up, everyone is upset, etc and then it fades out. Things are calm for month or two (they watch Internet boards too and will stay away while things are "hot"). Then it happens again, over and over and over. Empty talk, writing to various authorities (I am all for it, but..) is obviously not having an effect. So if something is to be done, it must be the community. I'd take it offline, seek suggestions/support of organized hiking clubs (such as North Shore Hikers perhaps), biking organizations, etc. and then implement solution. Otherwise just put up a cash box by the map at trailhead and paint in red "For thieves, help yourself but please leave my car alone" then everyone who passes chip in a 20.
I hear what you are saying but I see it differently.
I don't know who these thieves are but I'm going to assume they have knives and maybe guns. They may also be under the influence of drugs or alcohol when they are committing their crime. Any kind of a stake-out or direct confrontation is completely out of the question for me for safety reasons alone. If a volunteer were to arm themselves to be prepared for a conflict then they would be putting themselves at serious risk of ending up in prison. I've tried thinking through various approaches (could you hide in the bushes and have someone lock the gate once the crime is committed, etc.) and none of them end well.
Trail cams worked for the case in North Vancouver but I suspect the following: They already has a suspicion about who was doing it. The crime was being committed during the day. They were able to put the camera beside a trail so they could get close-up pictures, etc..
Setting up a trail cam for the parking lots would be more problematic. It would pick up hundreds of pictures of innocent people (and would the volunteer be putting themselves at risk of a lawsuit by performing covert surveillance in a public place?) Pictures of the subjects at night would likely just be a bunch of people in hoodies. It would be very hard to position the camera on the side of the road in such a way that it would be unseen but still capture license plates.
On the other hand, the official agencies can get around all of these problems. A cop can perform a stake-out or use a bait car or bait property (which have been very successfully used in downtown Vancouver,) and can apprehend the suspect safely and without breaking any laws. The park can set up a camera system that does not have to be hidden. etc.
I'm all for volunteers contributing to their community. Trailwork is a great example of where that can work. Crime enforcement is a lot more tricky. We pay a lot of taxes and I think that we are proposing some fairly basic and affordable steps that would dramatically increase the security at the trailheads. I don't think that we have applied nearly enough pressure to give up on the official routes just yet.
Here is one possibility: Volunteers could sign up to camp at the trailhead on weekends. It wouldn't be a stake-out. They would have a clearly signed area indicating that they are the "parking lot host". One challenge is that camping is illegal at Rubble Creek due to the Barrier so an exception would have to be provided (is that right?) Another challenge is that it wouldn't catch the criminals - it would just deter them and move them to another trailhead.