[De_Delph]

That, or to prevent the tracker in more expensive cars from doing their job. In mainland Europe, some high end cars need to be fitted with a GPS tracker for insurance. Thieves will try to jam GPS to those trackers until they're: A) figured out how to disable/remove it, B) fled the country.

[IndrekR]

Not just high end and insurance. In EU 100% of new cars have GPS installed. This is used for intelligent speed assist and eCall that are now mandatory.