It's been a while since I had to place lav mics in the heinously noisey professional uniform.
Last time, it was B6 through the buttonhole with less-than-stellar results.
This time, there will be mostly uniforms and I want to use the DPA's I've come to favor. Their "snoot" through the buttonhole seems to be a likely answer, but I'm thinking that it might be better to go through a hole made through a pocket or behind an insignia/medal and leave the mic more exposed than hidden.
Let's talk military / police / EMT uniform mic hiding techniques, shall we?