Mr Guberfield: The outline of arms is not as problematic from a tznius point of view as the legs. As for the upper part, if the outline is not hidden sufficiently then this is indeed a tznius issue. As it stands, plenty of ladies top garments do hide the outline.
It’s to do with what is liable to attract undue attention and cause improper thoughts rather than logic.
I think Oomis raises a good question regarding culottes, I can only surmise that the issue there is one of a slippery slope leading to less and less culotte type pants.
Mod-80 go easy, Mr Guberfield is surely allowed to raise a valid logical point as long as ultimately he defers to whatever is paskened and he has not given any indication that he wouldn’t. He was just trying to understand. If you feel I am wrong to defend him, please post back.