My guess is that missydarlin has it exactly right. Human Factors 101 says that if you build a technology with a non-zero false error rate, the human operators will soon learn to ignore the error messages. This is true with all the warnings you get when you use your web browser, and it has also been cited as the cause of some airplane accidents (pilots assume the warning is erroneous--"that warning light comes on all the time"--and just ignore it).

I don't see a way to fix it in this situation. As missydarlin pointed out, passengers do lots of things to their BPs that render them unreadable, thus a "false error." GAs are already under pressure to board the flight quickly, so the chance that they will invoke the manual override is extremely high.