Let us not forget that tracking users is not a single use case. Closing off cached resources when a user vanishes is a good thing, it saves resources for other

Let us not forget that tracking users is not a single use case. Closing off cached resources when a user vanishes is a good thing, it saves resources for other users and could, if I may stretch a little, have environmental impact. Noting that sessions tend to end after a particular set of circumstances could mean spoting something in your application that is annoying people, something that particularly in an SPA you might otherwise not easily detect. Sometimes tracking is legitimately benign. It is only when unnecessary PII is included, and kept to track each specific user over time rather than just over a session, that it gets stalky to the point of begin in my "I won't do that" list (sharing the PII around further gets you on my "you are morally wrong for doing that" list). > surprised they didn't even mention it as a possibility The article is focused on detecting when a user leaves. While a fair amount if that will be detectable because they've clicked a link, it doesn't cover the large case set that is closing tabs and windows. Something I might have to investigate (or search to see if someone else has): do any of these techniques work reliably on controlled OS shutdown.