I had not heard that DJ wasn't making his thingy any more... very interesting. One thing to understand... the DJ thingy isn't "approved" by the SCTA, it's accepted. The rule was written to allow engineered and tested SFI 38.1 type systems because at the time, there weren't SFI rated devices that would work on all types of vehicles. This was specifically to allow flexibility in allowing participants to use something that would work as an effective forward head movement restraint device rather than nothing. The DJ system had in fact been tested by SFI, and failed to meet 38.1 specs, but the data proved that it was very effective as a forward head movement restraint device and that's why it was accepted.
A reminder: the tech and safety rules as printed in the book are the SCTA's minimum standards. Nothing says you can't go above and beyond the min specs. Case in point: the new Dannenfelzer streamliner chassis was built from 1.75"od x 3/16" wall tubing but the min spec is 1.625"od x .125" wall. If you were shooting for 400mph would you build to the min spec or to a higher spec that you know is probably safer? If you wanted to potentially decrease the chances of getting killed by head/neck trauma sustained in a crash, would you use a SFI rated device or a SFI-type device?
Now that there are more and more devices available and especially ones that can work in laydown type vehicles, we might see the day where ONLY SFI rated devices are allowed. Bob, you seem to be very concerned with this... instead of wondering who or why or this or that, why don't you submit for a rule change requiring that only SFI 38.1 rated devices be used?