As a Range Officer, I shudder to think how a "simultaneous" crossfire would be managed on Hexta & Kongsberg targets (the ones I'm familiar with).
Here, if a target is scored with two hits, which indicates two shots fired close to each other, then the shooter is given the higher value & granted a convertible sighter. The same currently applies on our ETs. Whether or not the transgressor can be found is immaterial & the offended shooter can continue without significant or unmanageable disruption.
Now Hextas, I have been told can discriminate between shots to 1/100 of a second. So with a closely previous or after crossfire, a shot will appear after X delay, followed by another one when - a short time later or after another X delay? If it's the latter, then the shooter could well adjust his sight/aim if necessary & drill off a shot before the second hit on his target appears and the possibility of applying the Aussie crossfire rule would not be able to be applied - and remember we're then waiting for the third shot to show up.
As it appears now, there's a second or so delay before the result is propagated & we have the opportunity of applying a precise definition of what is deemed to be two simultaneous hits on the target, ie if the shots show up 1,2, it's an acceptable simultaneous hit; if it is shot 1, yawn, stretch shot 2, then it's obvious that the latter shot can reasonably be assigned to a subsequent crossfire & discounted without a sighter being warranted.
On my range, we require that shooters not proceed with a subsequent shot before the scorers confirm the shot. Of course that delay won't equate to paper marking, but it precludes the liklihood of short range benchrest shooting cadences.