I've always kept my stuff off site in a storage facility. I've never had an issue and I pay a few dollars extra to have their insurance plus mine cover my stuff. The facilities around here have management live on site. I know this isn't bullet proof but it allows me to keep what I actually want in the garage.
Now that I think about it, that would actually be very convenient for me. I never thought of it that way. So your stuff is covered through your insurance, and you also have insurance through the storage facilities? I had no idea they offered insurance on their properties, that's pretty smart though. Heck, I have a storage unit facility on the other side of my privacy fence. I could probably get a unit for free from them. They have an area to store boats, cars, etc. in the very back and the vehicles on their property kept bumping into our privacy fence and it started looking raggedly. I went and had a talk with them about it and they installed new concrete parking stops for us and I built a new Cedar fence to replace the old one! That's a very clever idea though, thanks for that tip!