(CHICAGO) The TSA put on a demonstration today showing how security lines can quickly get backed up by unprepared passengers.

They say it’s just a coincidence that the TSA put on the demonstration after hundreds of people endured long lines and missed flights earlier this week at O’Hare and Midway.

“This is not a red hearing. In fact …we wanted to do this event for more than a month. The timing, of course, with everything else that’s going on in Chicago, is kind of thrown us into making it look like were trying to use passengers to cover it up,” said TSA spokesman Mark Howell.

And while he’s not blaming the flying public, Howell says there is some shared responsibility there when it comes to things like talking off your belt and not bringing liquids through the security line.

“We are not here today to blame this on passengers. But this is one contributing factor to the lines. In preparation to coming to the airport, just take five minutes and look through your bag,” Howell said.

U.S. Sen Dick Durbin (D-IL) says more screeners are on the way and U.S Sen Mark Kirk (D-IL) says if the understaffed situation isn’t solved by Memorial Day the TSA administrator should resign.