I think that the "added delay" issue will have no more of a right answer than the "shut down or idle on failsafe" question- Ask ten different people, and you'll get 10 different answers.

SimJet's ECU introduces a 0.5 second delay in all cases. So in the case of loss of radio contact with my 9ZAPS, there's a 1 sec delay from the Rx entering hold to commanding shutdown, plus the 0.5 seconds delay for the ECU to accept the shutdown command. (Total 1.5 sec for radio LOC) In the case of a commanded (or emergency shutdown) it's the time it takes for me to get to the kill switch plus 0.5 seconds.

Is that a safety hazard? I would argue not- I still had time to get things shut down after my Facet mid-air'd at Superman.