Erm... no obvious places to conceal a weapon? I carry a gun every day (not a cop, just a citizen exercising my right), concealed, and you would not know it just by looking at me. And that guy was wearing baggier clothes than I do. Given the examples of public figures being killed, you could make an argument that the officers present figured that any guy who is acting erratically and not following their orders might try to hurt the senator. Unless you genuinely believe your life is in danger, it's just not a good idea to do anything except comply with instructions from an LEO. No, it's not always right, but if the officers were in the wrong, no doubt some lawyer will be chomping at the bit to sue the shit out of their department.