San Francisco's Assembly Bill 716 went into effect yesterday, granting all BART employees the power to ban anyone who urinates, defecates or participates in any other disgusting and illegal from the transit system. Smaller infractions—for example, treating the escalator like a public bathroom—will yield a citation, and three citations amount to a ban.
Bans will last 90 days to a year depending on how repugnant the act is. So yeah, BART passengers: clean it up. Not literally, though that may be a fitting punishment.