Folks, I hate to say this, but be it car, truck, motorcycle, atv or rv, if a thief is skilled enough, desperate enough, what ever, they WILL get your "thing" if they want it bad enough.
I was a for many years car eclectronics installer (including alarms) and trust me when I say this, alarms are mostly ignored anymore and a poorly installed alarm is extremely easy to by-pass.
Proximity (radius) sensors are only so good, but remember, it puts an invisible "bubble" around it, so what happens when that neighborhood stray cat gets too close? Motion sensors are a joke, setting them properly is near impossible. You set them on a flat level surface and park anywhere not level and they are off. You set them too sensitive and fart near it, they go off, you set it "higher" and they may not work when you want them too.
Now, on the flip side, they do help with insurance rates if professionally installed and they do provide the owner a little piece of mind, but even the absolute most expensive and "best" alarm WILL NOT stop some one truly desperate.