It’s not dissent if nobody sees it:
Preventing Demonstrators: As mentioned, all Presidential events must be ticketed or accessed by a name list. This is the best method for preventing demonstrators. People who are obviously going to try to disrupt the event can be denied entrance at least to the VIP area between the stage and the main camera platform….It is also not the responsibility of the Secret Service to check the tickets of the people entering… It is important to have your volunteers at a checkpoint before the Magnetometers in order to stop a demonstrator from getting into the event. Look for signs that they may be carrying, and if need be, have volunteers check for folded cloth signs that demonstrators may be bringing to the event.