Problem with autocomplete=off is some morons think they should use it on their login form for "security" or whatever, cause forcing users to type in passwords is "secure". So browsers wound up having to ignore it for actual security.
Browsers could have instead allowed me to right click and say "insert password because I know what I'm doing". But browsers are in the business of training users to be stupid, rather than acting as a user's loyal agent, so I guess we were mercifully spared this future.
I am one of those morons who had to build a page for someone to go to the nurse's office and input all their information without it being saved for the next person who goes there to fill their information.
Problem is we (my development team) didn't own the tablets, some other team did so we couldn't force the tablets to have in private browsing.