Not as easy as it looks.
Some people are giving the folks in Arizona a hard time for mistaking fire debris for Shuttle debris. I think one piece was actually a chunk of burnt toast.
Not everyone is up to speed on what a Shuttle is made of, or what debris might look like. It takes an eye that has seen a lot of space hardware to pick stuff like this out and nail it down as a piece of the Shuttle. The average person who wouldn't have any idea what a tile looked like--and why should he?--should be cut a little slack.