That is true. Chatting on the phone is a great method.I usually approach slowly and ask what time it is
Otherwise, if I want to spend several times in front of the same busty woman I pretend to be talking on the phone and I stay with glasses facing her. Usually, less attention is given to a person who talks on the phone and who seems to be thinking of completely different things (sorry for my english I probably wrote bad, but I hope you understand)
A method that has been described to me is to carry my phone in my shirt pocket with the camera pointing out.
I've tried this a couple times, but ended up with great footage of the ceiling!! LOL