Few facts first:
Houses were introduced in Update 6.4 2nd November 2001.
As per announcement on 16th October 2001 Tibia.com said: When we introduce Premium Accounts, the complete Tibia map will be reset to a fresh state. All people who store objects somewhere on the map should move these objects to their depots. Only items in the depot will be safe. Note, that in future updates all items in rented houses (e.g. flats or guild houses) will be safe, too. which means Cipsoft carefully was considering housing option for players and I am sure they also consider it as a protection zone. It also means that houses which been previously open for everyone were like any other ground in Tibia and you could have been attacked over there.
The video is from 1999-2001- I believe before houses been introduced.