We have assumed--everyone connected with the case has assumed--that the police, who did not know DeBerry's name and therefore did not know that he was a felon, knew, or at least had reason to believe, that if he was carrying a concealed firearm he was violating the law. They did know. It is a crime in Illinois to carry a concealed gun, 720 ILCS 5/24-1(a)(10), with the usual exceptions for peace officers and the like (720 ILCS 5/24-2), exceptions unlikely to be applicable to DeBerry. Even if this were Texas rather than Illinois, and carrying a concealed weapon was lawful except for felons and a few other classes of ineligibles, the police would have been entitled to accost DeBerry and ask him whether he was carrying a gun. They might have a hunch he was a felon and so violating the law. It would not matter, so far as the Fourth Amendment is concerned, as we explained earlier. But if the asking crossed over to commanding, so that DeBerry was stopped, then it would be essential that the officers have a reasonable belief and not a mere hunch that if he was carrying a gun he was violating the law. But they would have a reasonable belief, because this is Illinois rather than Texas.