I don’t think there is any problem with listed breaker interlock systems nor does U/L and the panel manufacturers who sell them.
Once Harry Homeowner takes the cover off all safety went with it anyway.
He could just as easy bridge generator power to the utility with his screwdriver.
In real life the overload on the generator would trip as soon as it was presented with “the grid” unless we are talking about a serious pad mount generator. What do you figure inrush is on a 167KVA pole pig and all the locked rotor equipment in the typical 3-5 houses on the secondary? I doubt the medium voltage side would bump. If it did it would hit the grounding strap linemen are trained to use before they touch anything.
I really think this “kill the lineman” stuff is BS.
You might be able to kill your neighbor though if the secondary is broken before you get to “the grid” and he is poking around where he has no business.