Profiling

In watching the news about the New York City shooting it was mentioned that the FBI has gone to all the truck rental agencies in the area warning them about the possibility of a terrorist using their truck. My question is, what did the tell them. Did they say that all renters should be checked with the same scrutiny or did they make allowances for appearance? Should blue-eyed blond females be checked in the same way as brown-eyed males? I think they are indirectly telling these rental agencies to pro-file without saying that. I believe that happens on a regular basis but no one talks about it. I believe that people use their common sense and in cases like this understand that a 70 year old grandma is less likely to be a terrorist than a 25 year old male with a middle-eastern look and they act accordingly. Even the greeters at Walmart tell me that they more closely watch teen girls than other groups.