I had to shoot a picture of this sign--but I did not dare show any real interest in those "genuine fakes" because the seller probably would have pressed hard to send me home with one of those watches..
Unfortunately, the high pressure sale is mixed with the legitimate walking tour in some places. Guides who will lead a quality walking tour will also see nothing wrong with taking you to a friend's business under the guise of seeing local industry or experiencing the culture. This isn't always a bad experience, but it sometimes results in unwanted pitches. Often, your guide will get a cut of whatever you spend.
It pays to ask if there will be any visits to area merchants on the itinerary. If the answer is "yes," don't automatically object. Find out more. I had a very interesting visit to a Turkish carpet producer near Kusadasi. The host probably was disappointed when I left without buying anything, but he did have a chance to show us some beautiful handmade products and the time-honored methods for creating them. There was little pressure to buy.
At other times, this is a much less pleasant experience. The pressure will be on you to buy something or risk offending your guide. Make it clear you are not booking the tour to go shopping. Do that on your own and use the guide's time for exploration.
