I think a lot of this goes back to good old common sense and advice Bear and Jenn have given. Our DNA is coded to protect us. If a place doesn't give you a feeling of security or at least safety, you best move on. And Jenn is right about people coming over to you right away. The last trip we took this summer, I was backing the trailer into a spot and a guy was trying to get my attention to ask me questions. I told him I would answer everything if he helped me avoid a pole I wasn't able to spot in my mirrors behind me. I also agree that if you befriend your neighbors, that increases security. It is kind of an unwritten/unspoken code.
The same thing applies to my neighborhood. We all know each other and look out for each other. We have very little crime on our roads, even though we are very close to the freeway/major roads. We are kind of hidden in a pocket though and I haven't had any trouble with it being parked outside. Having grown up in a college town, I learned early if it isn't bolted down, it could grow legs. Some places are better than others when it comes to storage. I think you should be good keeping it in your garage, but you know your area better than anyone else and need to do what makes you feel safe and will help you sleep at night. This is supposed to be fun, and not something that fills you with worry. If a tracker is helping, than go for it!
I will say that when I leave the trailer, I take all valuable with me (things that if lost, would ruin me...I.e. my phone, credit cards, etc...everything else is 'stuff' and I haven't spent loads on it, so if it goes, I might be bummed, but I don't worry about it), I keep all curtains closed, use the claw on the wheel, lock the chains and receiver, put down the chocks, the leveling feet are down, and we have a block that goes under our front wheel. This is all a deterent, and hopefully someone would notice someone doing all this work if we were away. We also have the trailer insured, just in case. Plus, I think it is more likely to be in an accident than stolen, and the insurance covers that as well (at least the part not covered by my car insurance).
Good luck!