Reminds me of the day at the pool when a well endowed gal newbi stepped out of the water to shower down before locker room and discovered how little her WHITE swim suit concealed her naked body. Actually, swimmers are so used to near nakedness, no one really stared/cared so she didn't turn red/pink like that bra.
Casual in the old days = formal in these days, it won't be long until everyone wears their PJs to WalMart & BBQ places.
It's not something that makes me think anything. My guess is they just had errands to run and didn't feel like going through the whole "routine" for grooming just to pick some coffeeor laundry deteregent up from the supermarket.
I wear neon sports bras or tank tops under white t shirts or yoga tops (loose) often on casual days. Not really trying to "send a message" but it's cute, looks good on me and you can't see anything so why not
I don't see it as a big deal if its a sports bra. I mean you can go to the gym and see a girl without any shirt just her sports bra or a girl out jogging like that. If it was was pink lacey bra then I think it would be inappropriate. Girls and now wearing the cropped shirts that have their stomach showing so the sports bra is fine.