This does not exempt you from any extra screening. It’s more or a “hey FYI guys, I can’t stand on my own / I will set off the metal detector / etc”.
My father has something he needs to communicate–that his knee contains metal and will set off the alarm system.
So he travels with a notification card and medical documentation because he figures it will be better for TSA to know that he’s about to set things off with his knee.
However, he’s found in using this card that all it does is seem to annoy TSA agents.
Some of them wouldn’t look at it and some of them were not so kind about it.
One agent laughed at him and asked why he bothers pulling that out if it doesn’t do anything.
My father figured the original purpose of it is to alert the agents ahead of time that he’s about to set off the metal detector. They see that heads up as an inconvenience, but the website on metal devices suggests he give the agents a heads-up.
Whether he’s on the scanner or in a metal detector, something weird is going to show up on his knee. But what do you think–should he just give up on alerting them ahead of time and wait for things to alarm? Or would some agents appreciate knowing this ahead of time?