Seven Ways That You Can End Up On A Terrorist Watch List. One of the links is to the Actual Guidance for the Watch List - it's a year old, but you'll get the idea.
Notable for its absence is consideration for due process - you know, that pesky old Constitution thing? I can scarcely believe that a fine, upstanding Senator such as Chuckie Schumer would ever have anything to do with unconstitutional stomping on anyone's rights. Knock me over with a feather.
And once your on a list by error or any other reason it’s very difficult to find out why and if by error to get it corrected. I don’t trust the government or their minions to not add people to the list they don’t like or disagree with or that the administration doesn’t agree with. What would happen if the IRS were in charge of “the list”?