Insurance is cheap. They keep it cheap by having you sign that nothing that could damage other stuff is being stored. And by having you sign that it is all at your own risk.

Heck you don’t even need commercial property. I know people that had a chunk of land in their back yard. They built the storage facility, had that chunk re-zoned, and BAM, they have a storage facility. Heck they get to write off their house as a business expense because they sell that someone is on site 24/7.