Not sure why your Hyster guy told you that. The new Hysters and Yales have a system on them that has to be used all in unison with each other. Operator has to be on the seat, seat belt has to be latched and foot needs to be on the brakes before starting. When I was working for the Hyster dealer two years ago it was about three days after we recieved the first machine with that system, when we got the service gram advising us on how the system worked. So we looked like a bunch of pinheads pushing this machine into the shop when we could not make it move.

Now if you want to retrofit some older machines I do believe an aftermarket kit is available. 15 years ago I did it from scratch on 12 machines for Martin Marrietta. Their techies helped me out a little by making a couple of pieces I drew out for them.

If there is a will there is a way and I guess the skill level of the tech helps also.