My two yen on the subject:
I personally worked with keyfobs and receivers for one of the "Big Three" Detroit automakers in the late 90s.
This particular receiver device, which BTW was used on their flagship models, had the tuning achieved with an LC circuit, in which the capacitor was a X7R ceramic.
You read that right. X7R ceramic. With all its temperature drifting and aging issues.
The receiver was a Philips one, and their app notes indicated the LC circuit tuning, albeit they indicated a N25 capacitor (to compensate for the inductor's drift with temperature).
Low receiver sensitivity, specially in cold winter days, was the #1 cause for field returns for this module, which not only had the remote transceiver but also a CANbus multiplexer and other supervisory circuits..
Now....this was with a single manufacturer 20 years ago. I ignore whether other manufacturers at the time had similar circuits, or whether this practice continues today.