Let me tell you a true story how it works.
In 1992 I was living in Jacksonville, FL. Governor Clinton was campaigning for president. They announced that an OPEN townhall meeting was going to happen at one of the local TV stations. The commericial told everyone to come and ask a question. I figured what the hell. I arrived a couple of hours ahead of time and found out that a ticket was needed to get in. I asked where do you get a ticket. I was told that from that woman over there. I went to that woman over there and she said she had tickets. She wanted to see some ID and she had a list of registered DEMOCRATIC voters in Duval County. I told her that I was a registered independent. She slapped the book shut and said that no tickets were available. I told her about the radio ad and she said this event was for democrats only. I told her that was false advertising and illegal. She said that it was not her problem and if I didn't move along then the Secret Service would detain me (a threat!). I hung around the edges and saw Skippy (steponallofus) having everyone line up and giving them index cards. They were supposed to put their questions on the cards. Further down the line they picked up the cards (while the voters still stood in line with a temperature of 95 degrees. Later it was revealed that the cards were handed back to certain people and were told to ask the rewritten question EXACTLY how it was written on the card. Afterwards, the TV station put on a BBQ for Clinton while outside the perimeter there were more protesters than there were supporters. You all watched the finished product on TV that night. It was broadcast nationwide.
A couple of weeks earlier I was working downtown when George H. W. Bush came to the Landing. From my vantage point at a parking garage I could see close to 100,000 people waiting for the president. That same TV station reported that "a few thousand people" showed up for the rally and presented strategically presented video to show a small crowd. Didn't get to see the actual rally as the Secret Service ran us out for security reasons.
I think Mel Brooks had it right; Tickets! tickets! We don't need no stinking tickets!