As my tweet indicated, I don't know what compels people to go shirtless and shoeless on BART just because the weather is hot. I really don't enjoy seeing people's sweaty bodies up close and could also really do without being forced to catch glances of people's feet. OK, it wasn't that many people going around without shoes and shirts but I did encounter at least 4 patrons like that today and 2 of them look like they were homeless.
You see that in Hawaii in casual eateries and the local Walmart but that's just the vibe and culture. On a BART train in the SF Bay Area during commute hours...not OK.