What security approaches have worked best for protecting construction sites after hours?

We've been discussing different ways construction companies secure sites that don't yet have permanent infrastructure. Traditional guards are one option, but I've also seen more projects using mobile surveillance trailers with remote monitoring and live video verification.

Some of the benefits I've heard mentioned include:

• Fast deployment for temporary projects
• Solar-powered options for locations without reliable power
• Remote camera monitoring across large job sites
• Live audio intervention to deter trespassing
• Incident reporting with video verification
• Coverage for equipment yards and material storage areas

I found this article that summarizes how tactical virtual surveillance trailers are being used on construction sites:

Hardening construction perimeters with tactical virtual surveillance trailers

I'm interested in hearing from people who have actually used these systems.

• Did remote monitoring reduce theft or vandalism?
• Are mobile surveillance towers worth the investment compared with on-site guards?
• What challenges did you run into during deployment or day-to-day operation?

I'd appreciate any real-world experiences or recommendations.