i had to laugh,..really!
we sometimes upgrade our guests because when they book the cheapest and smallest unit with us,..it would be a nice thing to do and upgrade them to a unit thats much more spacious and with more amenities.
what wording the caretaker used i dont know, but obviously we dont or actually cant force you to leave a 5 star review when accepting the upgrade, because the reviews are being done AFTER the guest has left.
what our caretaker meant for sure was this,...we want you to be comfortable and move you up into the larger part of the house in hoipe of getting a good comment,..not more not less.
same like when you book a economy class plane ticket and get upgraded to first class with more legroom, space etc.
very sorry that you understood it wrong,..but we learned for the future and wont offer any free upgrades anymore, only by paying the difference :)