Would u let your 13 year old walk around shirtless and braless in front of your boyfriend

I was talking to a co worker at work and she said she lets her daughter (who's very developed) walk around without a bra or shirt in front of her boyfriend who she's only been with for a little over a year. She said since the boyfriend has older daughters he's already seen that kinda stuff so it's nothing new. I know I'm judging but wtf! does this stuff actually happen. IDC if it's the biological dad I would never let my daughter walk around like that.