There’s no deduction anymore, luckily.
Depending on where the mesh is a clear strap bra might not help. My daughter’s leotard this year has mesh at the top in a way that’s impossible for the actual bra part on the front not to show through. The leotard was obviously designed by a man… but the leotard companies should do better and require it to be lined over the bra area. It’s annoying to pay $500 for a leotard that’s impossible to wear a bra under without showing, especially the front, not even just the straps. Even if it’s not a deduction it still looks messy, and it bothers the girls.