I've encountered telephone login systems which ask me to type in my password in its numeric form (e.g. if my password was 'password', I'd type 72779673)
If JetBlue has a similar logic system via the phone, I can see why Q and Z or prohibited to allow this existing authentication system to work.
Another interesting feature might be notifying the engineering team that a following list of bugs will be automatically disclosed in x days and give them a chance to review them with a fresh pair of eyes.
Pretty cool idea, but given that the target audience are people living in China, why is the site in English instead of Chinese? Is the target Americans or other English speaking people living in China?
If JetBlue has a similar logic system via the phone, I can see why Q and Z or prohibited to allow this existing authentication system to work.