At least she did before the harness. She would lay on the floor and stare at herself in the mirror I normally propped near her and sometimes she would even fall asleep. Now that she has the harness tummy time is a different experience. When she has her harness off she still just lays on her belly; however, if she has her harness on she doesn't seem to be able to get comfortable and ends up laying, with her face on the floor, in defeat.
I really recommend a pillow or rolled up towel or something. Froggie still gets some tummy time out of her harness or at least with her feet free.