Absolutely not the same. At no point does the window shopper or the person trying on shoes announce that they are going to buy. They are simply doing what you do when you look at all the adverts or make a general enquiry. People being late is not malicious intent similar to people not going to the doctors, although anyone missing an appointment should let their surgery know they are not going to make it as that is common courtesy.
Here we are talking about many (if not all) deliberately and intentionally making firm bookings they have no intention of keeping with no other reason other than to get their jollies or obstruct that person from reaching their necessary earning potential for that day.
The fact that you can't tell the difference to me says a lot about you.