Two more uses: Air conditioning and bottled water (and a water bottle for refilling). Examples: The - literally - very cool three-story BK on Calle Florida in Bs As in early February, and the McD's on the piazza at the Pantheon in Rome during the 2003 summer from hell.

And ditto re using the loo at any. I have heard that it's no big deal to walk right through a cafe in Europe - only - to use theirs (is this so?) but must admit to an internal cultural hangup, I guess, that keeps me from doing it. And I do see a lot of Europeans walking through McD's just to use theirs.