no idea about the antenna, except that it would be an excellent idea for them to put an interlock switch like that...at least to an alarm or light.... maybe not a kill switch though....
I'm reminded of the Nissan pickup truck I had way back in college. I think that thing was a 1984 model. I'd be driving down the road, then randomly every now an then....not often...the thing would just die like someone flipped a switch. I got real quick at hitting the clutch and rolling to the shoulder. I found that if I kept trying to restart it NEVER would....but if I'd just let it rest for a couple minutes, it would restart every time, like nothing ever happened. i never could figure it out. ended up taking it to a mechanic, who eventually figured out it was the relay that controlled the electric fuel pump