In the late 90s at my first job I would invite all my housemates to my office after hours for LAN parties using my co-workers computers. There were no logins and it didn’t even bother my co-workers unless a newly installed game took up too much drive space.
I feel we viewed computers more like expensive toys that should be shared rather than than the highly personal items they are today.
I think at that point we were still thinking of computers as expensive tools to be shared; it hadn't been that long since a computer took up a whole room and would be shared by all users in several businesses. We also weren't as concerned about security because most of the really important business stuff was locked away on the mainframe.
I feel we viewed computers more like expensive toys that should be shared rather than than the highly personal items they are today.