It smells like a shortcut a bit too easy between a general survey on holidays and a clear explanation of why people check their identity papers so early.
The model I see, but which is not yet quantified, is that administrative caution is a second nature here, especially with the culture of cita previa.
We know that 75% check in advance, but is it out of fear of administrative delays or just out of habit?
To confirm this, we would need to ask the participants directly what drives them to anticipate the verification of papers, such as bad past experiences with bureaucracy, for example.