I think if you are driving around and looking in areas to see if you are like the area, it's not a bad thing. I think many times, especially if the market is a very strong market for sellers and homes are selling fast, a buyer can lose an opportunity. So I would suggest that the agent, once they know what they are looking for, just update them daily on what's coming available in the area that they are looking at. Then if they want to drive by and see if the property looks interesting then they drive by and probably at the same time go in and look at the property.
