It seems that for a witness to keep up with the ever changing doctrines, teachings, beliefs and ideas of the society is a way to identify a so called "spiritual one" compared to a "weak or non spiritual" one!
Just like the account in "Gideon's time", if someone did not pronounce the word Shibboleth correctly, they were viewed with suspicion or even killed!
So too, if one doesn't know the latest "truth", they are to be viewed with suspicion or caution!