What everyone repeats, no one has checked: a simple survey on vacation habits is not enough to explain the motivations behind verification of identity documents.
It is a surface observation, not an explanation of the practical constraints governing these behaviors.
In Belgium, obtaining a passport or ID card often involves making an appointment at the population service weeks in advance, which is not a planning habit but an administrative requirement.
The 75% anticipation is not proof of innate caution, but often the only way to avoid catastrophic delays for their trip.