Remote shutdown sounds reasonable, but opens up a host of issues...
What about bikes? Cutting a motor at speed could easily induce a tank slapper.
At what point do you implement the shutdown?
Who makes the decision?
Should it be automatic?
Never mind cheating by a competitor, a defeat switch inside the cockpit would be the easiest thing to rig, and as such, the remote wouldn't stop someone wanting an extra long run (granted it would be their last).
Any suggestion that compares El Mirage to a dedicated drag strip or that includes huge (and permanent or even just heavy) infrastructure investments are not going to happen. Volunteer organizations being what they are, unless you want to double or triple your entry fee.
Earlier I was against reversing direction, but in looking back at the 6 events this year, we had tail winds for the first 3 and headwinds for the final 3, so it would be a wash. As far as a competitor getting injured or dying in a reverse direction run into the pucker brush or the fence before Callaway's, better one of us than a spectator. We sign a release, and have to have some expectation that death could be the result of any run we make.
Reversing direction, together with some form of automatic motor shutoff so at least vehicles are not hitting the fence under power may be the cheapest, easiest and most effective solution.