I'm dubious about the real cause here, rather than the claimed one. You can pre-start cars to (for example) defrost them in winter. But they've got safeguards built in to prevent starting if in gear, etc.

Also, why on earth would you hit the remote start on your phone if you were next to the car, you'd have to log into the app, send the command, wait for the command to be confirmed ...

Far more likely, the person pressed the 'start' button whilst half-in the car, with the clutch pressed (assuming it was a manual box), then lifted off the clutch whilst going to get something from outside the car, forgetting it was in gear. Which would have been the same result as if it had been key started, rather than start button.

I think that must have been staged, to make whatever point the programme was trying to prove.

Remote start is a luxury fitting, unlikely to feature on a van, and almost certainly incorporating a safeguard preventing it stopping in gear. And in real life wouldn't the man have jumped out of the way?

Lots of after market alarm/immobisers have remote start options.

eg. www.clifford.co.uk/ProductPages/Security_RemoteSta...l

They may or may not have safety features ...