My perception of boondocking is out in a remote and rough area well away from any form of civilization and neighbors, and in over 50 years of camping I’ve never lost a single thing.And it's not all that unusual for me to be gone before daylight and back after dark.
You wouldn’t get a MH back in those areas so I think you’re probably talking about dry camping by yourself away from dedicated campgrounds. Regardless of one’s definitions, it’s a given that the closer to civilization you are and the easier the access the more risk you have of something walking away. And a MH would be a better target than a tent or small RV. But it would still be far safer than it would be in a parking lot in the city. Even in a campground I’ve only lost an ice chest once, and that was on a weekend when the cg was full of people from the city.
It’s not something I’d be overly concerned about, just don’t leave anything of value sitting out in plain sight and if you carry barbeques or generators or other equipment lock them up.