AS, to answer to your concerns and increase confidence in aircraft systems, it would be necessary to study CS 25 certification requirements together with the manufacturers design submission and system implementation.
Simply, aircraft instrument displays must not present hazardously misleading information (definition and risk level in CS 25). This requirement is often achieved by using independent sensors and some form of cross monitoring or confidence voting; where ‘bad’ data is eliminated or the display shut down to prevent display.
A simple analogy is like the glass half full, half empty dilemma. Arbitration between the two opposing views requires a third party and only then in avionics terms is ‘amalgamated’ data used.
The Boeing problem appears to be in the inability to prevent the display of erroneous data, either because arbitration has failed or the inability to determine ‘bad’ sensed data and thus shutdown the display. In terms of beer glasses, there is little value of agreeing half full etc, if the beer is already flat.
The Boeing problem may be similar to that of ice crystals and pitots, where either the atmosphere is not as expected or that the sensor is susceptible to unusual conditions (or both); in this instance water.
This condition is very serious and requires (technical) rectification in the sensing system; however as a side problem, human reaction to an erroneous display appears to have identified a further issue in the control system.
Meanwhile in our ill-experienced litigious society, manufacturers have to explain the basic responses to pilots.
Something like warning people who have been brought up and now dependant on automated alcho-pops and fizzy mixes, not to drink flat beer, which of course requires an understanding of what ‘good’ beer is in the first place.