To state the obvious, not everybody has Chrome, and not everybody has or wants the newest version. That's how it should be. By implying that it's ok to assume otherwise, you're (probably unknowingly) harming the community.
Just try not to presuppose more than is required. I might be unhappy with the newest version. Or, my device can't be updated due to technical or polital reasons. Or, the newer version does not work or is not available for my hardware or operating system. Or, I might actually be on a fork (or fake) of the software that isn't up-to-date yet. You see, there are tons of reasons...
So I do have a choice, right? HN is a pretty technical forum -- not normally a place for ignorant-consumer type viewpoints (no offense intended). Case in point, my version of "Chrome" (chromium on Debian) does not auto-update (I think so - It's the normal way on Debian, although I don't really use chromium but firefox).