Ideally, that's how is should work. In practice, it's not always as smooth. Sometimes the lineminders are control freaks.

A few months ago, I showed my home printed boarding pass with the TSA Pre✓ logo to the AA lineminder at LAX. She was not satisfied with just a cursory look and grabbed the boarding pass from my hand. After 20-30 seconds, I (not so nicely) demanded that she return it to me. She didn't. I yanked it back - good thing I printed it on heavy weight paper, or it would have torn - and proceeded toward the TSA ID checker. She started screaming that I pushed her - I had absolutely no physical contact with her.

Her colleague at the top of the stairs blocked my way to the screening area. I wasn't about to get into a physical altercation, so I reluctantly waited for their "supervisor" to come. He carefully examined my boarding pass and asked for my side of the story. He followed up by inquiring how long I thought it was reasonable for them to check the boarding pass. I told him that three seconds was more than enough time to verify that it has the Pre✓ wording or logo. He asked me what if it takes longer. I just rolled my eyes. I was then allowed to proceed to the screening area.

By that time, my flight was boarding, so I never got a chance to get names and file a written complaint. I looked for that overly officious lineminder the next few times that I passed through LAX, but have not seen her since.