LaTi lists 85 things that might get you on a watch list, if a Halloween G-man spots you in the act:
1) Use Google Maps to find your way around a strange city.
2) Use Google Maps to view photos of sports stadiums.
3) Install online privacy protection software on your personal computer.
4) Attempt to shield your computer screen from the view of others.
5) Shave your beard, dye your hair or alter your mode of dress.
7) Avoid eye contact.
8) Use a cell-phone camera in an airport, train station or shopping mall.
9) Seek to work alone or without supervision.
10) Appear to be out of place.