Geez Sno, what is it with you - experience AND common sense?
Put it this way, it amazes me how many alarmed vehicles did NOT have backup batteries. And that was BEFORE trackers entered the picture.
Of course satellite horns solved many of the alarm issues, but to have a tracker only to have the thief hide the vehicle and disconnect the battery...
As to dual systems, have I ever mentioned how much I like redundancy?
As for trackers, many expect one but rarely two. Of course a well hidden tracker with ONE obvious battery/supply and well concealed secondary (or is that tertiary?) power source may overcome the need for the expense of second tracker. But full redundancy means a second tracker - ie, if the first is found or fails. (And that should be triggered after a delay after the first quits/fails - just in case scanners are used. And it should operate intermittently...)
Funny how technology changes, but not the basic principles.
As a wise turkey once said - "[i]everything is the same... just different[i]".
Lets look at the situation. Lean burning is a killer to an engine. If you have a race engine not getting enough gas it will blow the engine in short order. I would be surprised if cars such as NASCAR vehicles don't automatically cut the ignition on a loss of fuel pressure. At a drag strip you are very likely to blow your engine if not getting enough gas while doing that 1/4mile run at WOT. Losing your ignition doesn't harm your engine as far as I know. If you do cut the gas you HAVE to also cut the ignition as well to protect the engine. At WOT you CAN easily blow the engine cutting the fuel pump without cutting the ignition since you are slowly bleeding off the pressure and running for a few more cycles. If you cut the injectors it may be different since no fuel is being injected. And most waste spark systems will spark on an empty cylinder..
And as otherwise stated cutting power while running down the road is dangerous and will leave the maker of the device liable for damages caused by accidents caused by shutting down the engine while moving. The Proper way to do this is to cut the ignition when the car has come to a complete stop. I would probably also make sure the brake pedal is applied to ensure the car is not rolling still.
As to secure connections.. You could have your vehicle check in every so often and if it doesn't get a signal to shut its self down and to prevent any starting etc. So hiding it wouldn't accomplish much.
My security system will have multiple backup batteries as will my CarPC... ;) Plus they will talk to each other making any attempts to steal the vehicle very annoying to the thief.
FTR, although rare, ignition cuts can blow engines, but usually not if fuel is also cut.
But I think the safety issues of any engine cutting when in motion (or on railway crossings etc) has been covered satisfactorily.
I know this is old but I just want to say something. a gas engine is turned off by cutting spark. A diesel is turned off by cutting fuel. If those two methods are used respectively then the engine should not blow up since that's the same way it is turned off when the ignition is turned off. Yes granted if its still in gear when the engine is turned off it may damage the engine but not too bad unless its done regularly.