remote kill is nice. my friends had a long lead on the back of it that a parent could wear on their wrist and if the bike got to far away it pulled the plug out the back, kinda like a jet ski.
These have that too. It's like a "dead man" switch. I guess you're supposed to tie it to a belt loop or something like that. In case the kid falls off, you don't have a runaway atv. Yeah, same theory as the jet ski.