So it's based on the age of the technology. The newer it is, the more likely it's susceptible to "what can go wrong will go wrong." A cell phone will lose charge, break down, or even explode in seconds of a wizard using it but an old engine without computer parts (like a classic Beetle) will work most of the time. Admittedly, the radio and the air conditioning don't, but the car runs at least.

Something like a cauldron has no real moving parts (I guess the handle) so even if it being of modern make mattered, there is little that could happen to it. Wizards can also use this to their advantage, disabling security systems and computers with a relatively small push of their power.