Scanning for those devices should be legal. Removing the device from your car should be legal as well (destroying it probably is not).
In my neck of the woods it is an option to turn the device in to the lost and found bureau or let the police get the device for evidence. If I were at risk to be harmed by a stalker, Iīd prefer the latter.
Those jammers are prone to interfere with legal operation of Bluetooth devices. Authorities might not be inclined to put up with that.

BTW:
APRS allows tracking too. I can legally build and operate an APRS tranceiver. I can also buy such a transceiver without prove of license. I cannot legally use it to track someone without their consent though.
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If it isnīt broken, it doesnīt have enough features yet.