Personally, I'd never could. I can't go less than a thong (can't do g strings nor commando). My mother and sister think it is fine to go commando with one exception with jeans, apparently only cheap prostitutes go without underwear with jeans, but that is my mother talking. But it's not really anyone's business really.
It's uncomfortable and it's kind of disgusting for a woman to not wear underwear at anytime seeing how us women have daily discharge, and monthly periods. Underwear prevent our clothes from getting ruined and just make us feel more comfortable.