Originally Posted by BeCarlson
To me, e-boarding passes seem to be a ripe opportunity for criminals to fraud airlines into flying them for free.
For instance, take the following scenario:
1. Obtain a PDF of a legitimate e-boarding pass
2. Edit details of the PDF such as flight number, date, etc using Acrobat Professional's retouch text tool
3. Check united.com to make sure the flight isn't full
4. Presto! You have a free ticket
Did airlines think of this when they opened themselves up by allowing passengers to print their own boarding passes? Don't jump to conclusions, I have NOT tried the aforementioned scheme myself, I am merely pointing something out that to me seems absurd.
I am rather sure that they did, hence the enhanced bar code used by the gate readers to check the e-boarding pass.
Since the bar code will not match the details edited on the pass, and cannot be edited, the pass itself will be rejected by the machine.