Ok, let's play.
I'll use your scenario and let's say you live where I do.
Have you ever heard of Slomin's Oil company? They have well over a million alarm accounts in the New York Tri state area. In my area there are more oi l companies in the alarm installation business than not, with hundreds if n ot thousands of (quasi) alarm installers, former alarm installers and subco ntractors, all having access to peoples homes and many having worked for AD T and other national alarm companies. There's much doubt by legitimate alar m installation companies in this area, that any great percentage of them ha ve gone through the state required background check. Employee turnover is r ampant.
So I'll base my argument on just that fact alone.
What are the chances some one of them might use this device? I don't know . ... but the chances would be zero with out the product being made available to just anyone who might want to do harm to a former employer or end user. And you give a lot of credit to someone who would do something like that b y presuming they would have the sense to understand that they "might" not g et away with it.
The premise that seems to be too hard for you to appreciate is that if the product wasn't available there wouldn't be any chance of it being used for nefarious purposes at all and that the manufacturer obviously doesn't care. Can you imagine what a miniscule market this device has, to make it even w orth manufacturing? So "what else" might it be used for if not only for leg itimate purposes? Do you think that the manufacturer "should" make a produc t like this if it even remotely provides a means for alarms systems to be i llegitimately bypassed? I don't think so. But, of course there's always som eone who thinks that "everything" is ok to do.
You personify the probability that ethics is well on it's way of becoming o bsolete.