just from my experience with dealing with brad at sommers, he's as big as a crook as the dude that stole your trailer. i wouldn't trust him either. if you actually get it back from him i will be amazed.
i just make sure mine is locked up behind a gate and can't be seen or removed :)
cause no matter what you do if someone wants it bad enough they're gonna get it. so you'd be better off putting a tracker on it for when they did take it.
i've used those same harnesses in mine(the ones you installed for the kids) for about 5 yrs with no problems at all.
the buggy is looking grreat too :D