According to my latest mail response from the Hawaii County Office of the Corporation Counsel, a Deputy Corporation Counsel claims that not one single "multi-burst trigger activator" has been either voluntarily turned in OR confiscated in all of Hawaii county. So that would mean, assuming that at least one such device exists in Hawaii county, that the current compliance rate is 0.00%.
I hope some of you in other counties can elicit the same information in your counties and inform us here.
As a side note, yesterday at a steel challenge match, one guy who had just installed a 2.5 pound trigger on his .22LR rifle inadvertently ran off a few bumpfire sequences (even with the extremely low recoil of a .22LR). But it is not illegal to bumpfire, or even bumpfire using ordinary devices like rubber bands, string, sticks, boards, pipes, belt loops, etc., at least in Hawaii county according to the Deputy Corporation Counsel who replied to my inquiry. Bump away my friends!