I am UK resident who spends as much time in Schengen area (Tenerife) as I'm allowed. When we are not in Tenerife we often take cruises. I understand fully why if a cruise begins and ends in a Schengen country the whole cruise would count - however can anybody explain or confirm what happens when a cruise commences and ends in the UK and there are just a couple of days spent ashore on Schengen countries during the cruise?
This related answer mentions that the 90 days start as soon as my passport is stamped at the port of entry. As far as I can determine from the cruise company there are no procedures in place to submit passports for stamping either on arrival or departure. I assume they may submit some a passenger manifest, but how would I know if any days have been reduced from our 90 day limit?