Get what makes YOU feel happy, LauraH. If you want locks and such, go for it. If not, whatever. I, for one, will not quibble with you.
Regarding insurance - yeah, everyone should have it. But, if your trailer gets stolen and you want a replacement, do you want to wait a year to get a new one? Or purchase a used one that may not be exactly what you had already?
Now that I'm using the trailer, I'd much rather spend time in it out and about, instead of not very patiently waiting a year or so to get a replacement.
For us, we opted for some security measures. It works for us and we're fine with that. However, I know not everyone will agree with what we've done. Yeah, whatever. It's our trailer and our level of security that we need.
We got some cheapo Master locks for the storage bin and the X-Chocks. Yeah, someone could cut them quite quickly if they wanted, but it'll slow down those that don't want to take the time to cut them. It only takes a few seconds for me to put them on and off. No biggie. Same with the lock over the hitch coupler (or whatever that black thingie is that goes over the ball hitch area and seats down when the ball is properly in place).
We got a bike type lock (chain lock with plastic over it) for the levelers (from Purple Line). Again, someone could cut it, but again, we're keeping the lazy thieves away and off to another site or rig at someone's house/storage unit.
But, what really gives us peace of mind is the boot clamp. The Nemesis from Purple Line. More than one person commented on it at the Spring NOG and said how nobody's gonna steal this trailer. I've also had more than one nearby camper come over to get information on it. One of them had his brand new trailer stolen from in front of his house. He was quite impressed with it.
If the trailer isn't hitched up to the truck and I'm not hanging around all day/night in the trailer, then it goes on. I've gotten better at putting it on. It was rather a bitch at first, but with many things, practice has made it easier.
I'm including a photo of the Nemesis, as well as the KoJack levelers since I mentioned them. We could not get the BAL levelers to fit, nor could an owner of a 5.0TA. I know others have, but we couldn't. Many will poo-poo this type of leveler, but they work great for me as I'm setting up and taking down on my own.
Here's the link to the Nemesis (there are other types/brands out there, but this is what we decided on)
Nemesis Professional Caravan Wheel Clamp | Trailer Accessories | Purple Line
I probably won't add anything for the propane tanks. Haven't thought about the spare tire - yet. We'll see about that later.
So, yeah, see to your level of comfort regarding the security of your trailer. Everyone has a different level and that's fine.