Originally Posted by
seat 1a
To my recollection this is only valid for domestic flights anyway.
That changed awhile back. It works on (most, if not all) international flights, but it's carrier-dependent. I just thought that if LH asks for the number, then they'd transmit it to TSA. Didn't matter in my case, though, as I forgot that Terminal B at EWR has separate security checkpoints for the different wings, so the checkpoint for LH didn't have PreCheck anyway.