TL;DR: Do stays in the Schengen zone while accompanying a family member who is an EU citizen count towards the 90/180 day limit? What sort of documentation is needed in this case?
Suppose a citizen of an “Annex II” country (allowed to stay 90/180 days in Schengen w/o visa) is married to an EU citizen. The Annex II country citizen can then, for example, stay 90 days in Schengen, leave for 1 day, and then re-enter with their EU citizen spouse and stay for another 90 days (or however long they want, for that matter, provided they apply for a long term residence permit when applicable).
Question 1: What about the reverse? I.e. suppose a citizen of an “Annex II” country stays in the Schengen zone for an extended period with an EU citizen spouse, and then both leave the Schengen zone together. Can the non EU citizen then return the next day and spend 90 days as a tourist?
Question 2: If this is indeed allowed, what sort of documentation is required? I assume simply rolling up to the border and saying “Yes officer, it looks like I’m overstaying, but actually my significant other was with me on my previous stay, so it doesn’t count!” won’t be worth much.
Of course, if the initial stay with the EU citizen spouse were for an extended period of time, then the non EU citizen would have applied for (and presumably been granted) some sort of local residency permit, which could be used to explain things. The point of the present question is what to do in other situations, i.e. when the stay with the EU citizen spouse was not long enough to need (or even be allowed to apply for) residency.