Its kind of hard on your clothes to wash them all the time. The point of underwear is that you wash (and wear out) underwear fast but are easier on your pants.
If you're wearing cheap pants, no big deal. If you're wearing dress pants, you really don't want to dry clean them every time you wear them. If you have some selvedge repo jeans you are hoping to not wash for 9 months till the fade is established, again, underwear might be in order.
I don't see why it wouldn't be acceptable, males and females alike. My ex has gone commando ever since high school. I personally don't see how he does it, because he's pretty well-endowed. I'm sure when stuff gets all bunched up in there, its not very pleasant.
my boyfriend goes commando every once in a while, apparently.
I personally wouldn't go commando, but I do wear tighter pants.
Anyways, I don't think there's really anything wrong with it? It's not like the general public will know.. heehe just me. But like, I don't know. there's nothing wrong with it. personal choice, I suppose.