I'm so annoyed - was almost done with a post and then I closed the window by accident and had to retype all of the below all over again
So, my take on stealing stuff (2nd time)
Wireless on/off - this must be some sort of matrix action, since you can shut off all of your wireless functionality as a free action (see page 421).
So, shutting off the wireless on a device is either a free action if you are the owner, or requires a Spoof Command action if you are not.
Remember that a Spoof Command action requires you to have a mark on the Owner of the device, and not the device itself. Which means that if something is owned by a company (like a company car) you can't
ever turn the wireless off, since you can't get a mark on the owner of the vehicle.
You can, of course, cut the power to a device, which will shut the wireless off on it. However remember that simply shutting a car off doesn't actually cut the power to it, you'd have to remove the battery.
So, for the commlinks for the cultists, you now have their commlinks. As long as these are on, their wireless is on, since you can't turn it off, since they are dead and you can't get a mark on them. If you shut them off, then no one can track you, but you can't access the commlink either.
Changing Ownership - if you want to become the new owner of a device, this requires the wireless to be on, and then the Hardware+Logic extended test requiring 24 hits with a base time of one hour for each time you roll the dice. Which means you better either have killed the owner, or make sure that whoever owns it doesn't realize it was stolen, since otherwise by the time you actually change the ownership of the device, he will have found you.
Big Ticket Items - Stealth RFID tags are essentially free at 10

a piece. With any expensive piece of gear, it is foolish to not implant several of these. With cars, these can be put in hard to reach places, out of the range of a tag eraser without taking the engine block or chassis apart.
You could of course find these tags with a Matrix Perception test, and then use Data Spike to crash the RFID, but of course as soon as you do this, it alerts the owner of the RFID that the tag was under attack - and if there are multiple such tags, then all he/she has to do is run a Trace on one of the other tags.