The "login/register" link has a workflow that encourages use of the Back button. This in turn causes the user to see stale pages.
Steps to reproduce:
1. Follow the "Log in / Register" link from any page.
2. Log in.
What happens:
* You are told that "You are now logged in as <whoever>", and nothing else happens.
* If you use the Back button to get back to where you were, it's cached so that it looks like you're not logged in.
What should happen:
* Logging in returns you to a logged-in version of the page you were on.
We know what page you were on, because it's the bit before the "/+login" in the URL. And we can take you to a logged-in version by adding something like "?gc7zy0" (or perhaps something more meaningful) to the end of the URL so that you don't get a cached version.
The issue is that the "login/register" link at the top of each page sends you to "/+login". This means that you must use the back button of your browser to return to your previous position.
If the link is changed to be the current URL plus /+login (also handling query parameters) then things would work as expected. There would be no need to use the back button.
There is no need to do special things to cope with cacheing. The site runs over HTTPS, so cacheing should not happen except when you use the back button.