I know the clue is in the name 'autologin'

But what behaviour should I expect if I tick the 'log me in automatically' box because I have tested it and don't see any real difference.

If I don't tick the box / login / then close the window and exit the browser then re-launch the browser and go to my site I'm still logged in

If I do tick the box / login / then close the window and exit the browser then re-launch the browser and go to my site I'm still logged in

If I do tick the box or don't tick the box then login then close the browser, after a few hours I come back and re-launch the browser and I'm logged out

So when you tick the box what actually happens then with the script? does it add an extra cookie or something? What behaviour should I expect? Thanks