Ah, man. You definitely have to feel bad for this lady. She's older, so maybe her eyesight isn't so good. She might have thought those Wet Paint signs were just random blobs on the street, or she didn't notice them at all. I like my Wet Paint signs in a little more visible spot. People are going to end up reading the signs right as they sit down. I guess it's better than missing a spot because of the sign, but I'd rather have a less-than-perfect bench than ruined clothes.
It sucks to have fresh paint on your clothes because you inevitably end up ruining everything around you. You can't sit anywhere new without messing it up, so getting on a bus or a car is a no go. You have no choice but to walk home like a painted idiot.