I think it really depends on how sensitive the light is. I trip about half of the induction loop lights with my steel framed bike (no magnet). The other half I don't. I actually had to run one (on my aluminum bike) the other day, there wasn't a car around and I'd waited through two cycles of the cross walk!

Maybe the OP should tell the city/county. They probably won't do anything, but I'd guess that if dozens of folks eventually register a request they'll consider putting in a motion system. It may do no good, but when a cop catches you running a red you'll have that official paperwork to bring to court documenting that this light doesn't work.