Yes it's called the Sport Ident system .

Used this year by

Polaris

RoughRide 

and tons of road events 

Since one has to insert a transponder into a slot and wait for a flash it's pretty much idiot proof

Every event I've heard about or run that has used this has had 100% success

I'd either use it or no electronic system at all [I've used the mat system  {once}] 

Since one has to insert a transponder into a slot and wait for a flash it's pretty much idiot proof

I know the one you mean. I don't think it'd be suitable for an event like this, we're talking about sub-two minute DH sections with fractions of seconds between riders. Stopping, rummaging out your dibber and sticking it the slot isn't, I believe, going to cut it.

Neither does the mat, so that means the event doesn't work.

Mind you if any of the timed sections goes on or even across a bridleway then the event is illegal and all insurence is invalid. Patrick Adams got caught out by this at Coed y Brenin.

FE were clueless, they hadn't even read their own protocols. 

Mind you if any of the timed sections goes on or even across a bridleway then the event is illegal and all insurence is invalid

They didn't.

How would one know?

They are not marked on the ground, so unless you study the definative map one can't be sure, although OS mapping is reasonably accurate