I’ve had a quick look and can’t see that it’s included with VW. I know I’ve read it on a few manufacturers/motability vehicles. Ford as an example by reading the boring small print it could save some having to upgrade or pay extra as some things are included and fitted to all Motability vehicles. Taken from Ford motability list:
[††]Vehicles shown are vehicles available on the Motability Scheme. Please note that these vehicles are subject to availability and you should check with your Motability Accredited Ford Dealer for the availability of your preferred vehicle. Where offered, Appearance Pack and Active City Stop are subject to availability. Rear parking sensors will be included on all new Ford cars contracted through the Motability Scheme by a Ford Authorised Dealer (if not already as standard).