I think the task unit might be better utilized as a key to be able to operate the forklift, in other words, only certified by employer operators are given a tag unit, that will then enable them to un-lockout the transmission in the unit they are authorized to use.
You may recognize I don't feel there is any possible better method than an alert, trained and caring operator to deal with the ever changing hazards around a forklift, and that safety devices that induce false security should be avoided as much as sleeping while driving should be avoided.