The way I see it, these are the options:
Indestructible tape,
Destructible tape, extremely agile trackside spectators and invisible walls
or
Destructible tape, extremely agile trackside spectators and the ability to go as far as you want, crash and that's it, race over. No ghost car resets. Maybe allow said agile spectators and marshals to get your car back on four wheels to continue racing (as is seen very often on WRC stages), but if you've fallen off a cliff, that's it.
Personally I'd be up for that, it would definitely help stop some degree of cheating by wall riding and would really make you think, rather than just go 'oops, too quick, maybe if I can get on the handbrake I'll hit the indestructitape® barrier sideways so I can get going again quickly'.