Most guys wear whatever they are comfortable with, although sometimes I happen to meet them after or within work hours so their outfit can range from a suit to even scrubs (if he is a physician), of course they politely request a shower prior to or after depending. I have seen guys wearing shorts, a polo shirt, jeans, t shirt etc, so I think it is just circumstantial. If it is an extended engagement the dynamics change a bit, I seem to think that gentlemen tend to plan a bit more in terms of elegance  (nice shirt, cufflinks, nice pants, loafers etc). I find that the sexiest thing a man can wear is confidence, because at the end of the night those clothes are coming off.
Kisses,
Paloma M.

Since I only do extended dates that usually end somewhere other than the hotel room, guys know to bring a change of clothes to go out. If the place we are going has a dress code, common sense says don't show up in shorts, and I can't say I have ever had that problem except once. The guy was true red neck lol.