Those 2 mentioned cars are fairly new. Did they clone the remote (signal), or actually steal the keys from inside the house first !? You'd think new(er) cars would be much more difficult to compromise their security systems built in.

Get some decent CCTV outside your property, as a visual deterrant, goes a long way! Along with appropriate "CCTV in operation" stickers.
Most bad guys dont like to openly commit a crime if they know every step is being recorded, plus can see the cameras are covering the premises.

It's also relatively cheap to fit additional physical steering wheel locks etc. Another decent visual deterrant. While they might not stop the determined criminal, a casual opportunist might see that over your wheel and decide he stands a better chance against a vehicle with NO additional security aids. All helps.