Oh god...! I hope I never see the day when you have to subscribe to a hardware device for it to work!
Too late:
- (not exactly needing a subscribe, but paying extra, so not that far) VW Golf V (and many other cars): The difference in wheelspeed between left and right side and it's response to acceleration and breaking is evaluated by the ABS unit, so the unit is able to differentiate between complete wheel slip needing an action and just "flat tire" slight slipping, needing a bit different response. That functionality is working in all cars, as it is part of the mandatory ABS.
But when you have paid about 500Euro extra, the detected flat tire will light up a warning light on an instrument cluster. Note the LED behind that symbol is populated on all cars as well, you may notice it lighting with the "Christmass tree" lamp check after switching ON the ignition.
- one of the Agilent "Mid range" "Infiniium" oscilloscope has two BNC's extra, labeled "GEN1" and "GEN2". At the same time there are two keys, again with labels "GEN1" and "GEN2". When new, by pressing one of those keys you activate a "generator" menu, so the unit works as a functional generator as well. But only for few months. Then after pressing any of the "GEN" key, just a window appear on the screen reading "To allow generator functionality, please obtain a license..."
- Credence MicroFlex family of automated testers for integrated circuits is in fact a kit, where you may assemble different cards according to your needs, of course there are software functions allowing your test program to use them. But with many instruments you sooner or later hit a performance limit. But how to go further? Not by replacing the card for some more advanced one, you just have to buy a "license" allowing you to set the card parameters further (e.g. sampling speed of a digitizer, memory size for the digital card, even things like range of available output levels of the digital outputs: Basic is from -1 to +6, with extra license it can suddenly drive -2..+10 or so). So most of the HW works with the most advanced properties they offer, but are artificially restricted...
But to be honest, with both cases above it does make quite a sense, as the manufacturing cost of the hardware is small fraction of the total expenses the makers had to pay, because these are quite technically challenging low volume products. The majority is the development and support cost (mainly with the tester; there are no more than few 100's of similar devices in use around the complete globe), which is linked to the top performance, so using 3x more expensive components for even the cheapest options to allow quick upgrade later is worth to spend.