A lot of people have learned exactly the wrong lessons from the Boy Who Cried Wolf. Making people complacent with repeated false alarms is more likely the intended outcome than a failure.

When I was in school, one of the history teachers spent a lot of time describing how the Yom Kippur War started. I guess he thought it told something important about how things work in the real world. The lead up to the Russian invasion looked pretty much the same. An ordinary person could not have known if the invasion would actually start this time. But a reasonable person should have understood that if an invasion was about to start, that was what it would likely look like.