I hesitate to throw my $.02 in here as every production soundman I have ever met has his/her own way of doing this and after a few years, usually makes it work.
Here is what I have found; the simpler, for me, the better. I use Sonotrims (uprated Trams) or Countryman B6 lavs, so all you guys who use Sankens and AT and whatever, yes, you probably have another method. The Trams sound best and seem to be the least scratchy in their vampire clips, grills into the clip and simply pinned into the wardrobe is the area of least contact. These work really well on polo-type shirts and open neck dresses where the cleavage provides a natural space.
The B6s are, more and more, getting poked out through button holes and secured behind the button with a tiny dab of Joe's Stuff: Joe's Sticky Stuff ™ ::: Homepage
This leaves the head of the mic on the outside of the wardrobe and just the tiniest little bit visible, which only the most anal and inexperienced DP will fuss about. If you are looking at the lav, the shot must be pretty boring otherwise, right? Some will give you trouble, most won't.
Of course, there are a thousand different and difficult lav situations, but we've managed, in many seasons of TV to mic almost everything successfully.
As to shaving chest hair, no woman will hear of it
and neither will most men. Sometimes, as well, there will be a situation that will be really hard to make a lav sound good. Just like any other situation that might come up for a soundman, we do the best we can, professionally and conscientiously, and we then leave it in the capable hands of the other half of our on-screen craft and let the post guys and ADR folks have a go at it.
BTW, in 35 years of doing this, I have tried every imaginable combination of foam, make-up sponges, moleskin, gaff tape, triangles, squares, tubes, hoops and bicycle wheels. Not sayin' they don't work, just what seems to work best for my team.
Remember, this is my opinion on the matter only. Everyone else, have at!