@henry I would also recommend "Cookie AutoDelete" (https://github.com/Cookie-AutoDelete/Cookie-AutoDelete).
With it you can just say yes to every cookie, which is especially important now that some websites demand to get to set cookies or else you must pay for the privilege of not being privacy violated, but then after you leave you just drop all their cookies on the floor completely automatic, unless you choose to actively whitelist a domain (or sub-domain).
This also makes it very easy to explain to not so techie people that if they feel like they must stay logged in at some website or have some website-configuration be remembered, then they whitelist but otherwise it will just keep dropping all the cookies on the floor after they have left (at closing of tab, with configurable timer for SSO-redirects and similar).
I would recommend you take a look at it, @hen as it makes every tab kinda "private browsing" but retroactively and undetectably, and again, for the ease of use for non-techies.