This was accidental, but it could certainly be done on purpose:

Some cars failed to start on Tuesday in Parrock Street car park, in Gravesend, Kent, while others would not unlock.

[…]

A spokesman said “weeks of sleuthing” by council officers had them looking for a rogue transmitter or wireless broadband unit in nearby offices.

Staff also checked all transmissions in and around the car park, because of nearby communications at the town’s Civic Centre and police station.

[…]

Ofcom was finally called and a survey found a small family car was intermittently sending out signals blocking other fobs in a 164ft (50 m) radius.