Most hosts know if it is prohibited to rent our their unit. And yet many, many people choose to violate the rules and jeopardize others safety. Why? Because of the money.
The profiles on the listings are often the people actually renting out the unit. But there are false profiles and pictures that are not from the unit. Those people, are hard to find, but it is possible.
If you try to contact the host through your Airbnb account, it will most likely be shut down. Airbnb doesn't mind encroaching on your property but find it unreasonable when you ask them to stop. You have to contact Airbnb who will then tell the host that they need to comply with the rules. But Airbnb will to take down the listing or sanction the violating host.
Many hosts also have social media profiles and list their units there. They are on Facebook and Twitter and Google+. Finally there is the option of pretending to rent a unit, just to get the unit number out of them. But that is also against Airbnb regulations.