You would hope that the four daylight bright LED's (one inside and three outside) and the fact that your in the van may have put them off in the first place, but you can elect to have vulnerable windows switched if your really worried
I think that the numbers of people that suffer losses with our Growler system fitted is extremely low, given how many times we are recommended
To the OP there was a good example posted on here last week where a Swift was stolen from a Funsters drive, tracked but not alarmed. The motorhome was recovered in less than two hours.
I was unfortunate enough to have our swift stolen last week, luckily it had a tracker fitted so it was recovered & secured very quickly by the police. My feeling is that being near Heathrow the police saw the alert very quickly, unsure how many police vechiles have the anpr equipment fitted in rural areas. They were close to finding the tracker in the vechile, and were probably going to remove it. We now have a growler & non start fitted for total peace of mind. So if your insurance requires the tracker have it fitted, if not just get the growler & non starter. Or belt & brace it and have all 3.