I recall reading once that it was brought up in passing in one of the (now fairly regular) meetings between NAR/TRA/BATF folks and the ATF guy basically said that for the most part, ignitors (starters) are mostly unregulated and ATF doesn't care to get into inspecting everyone's business. However, officially, as you noted, they ARE regulated. So his advice was that the best course was to leave well enough alone because if someone started making noise, the odds were good that everyone would have to have a permit and inspections. As it stands, its more of a "don't ask, don't tell" sort of thing.
I'm sure that there are a couple of folks who can relate this story in better detail and accuracy on the forum, but that's the conversation that I remembered.