I believe in dressing modestly, so I alway, always, always wear something under a low-cut top. It could be a flower-patterned scarf, a lacy camisole, or in this case a blue tanktop.
Wearing a tight tanktop in the right color not only add to your overall look, but also protects you from the oops-moment when you're bending down like in this picture of me. So it's very convenient. You can bend and stretch and run and jump and be comfortable without having to worry that anything's not supposed to be shown, be shown.