Is Free Wi-Fi a Scam?

Hi, l know that Wi Fi is legit in some places, library's are usually genuine, but l have found that in some shopping center's it is a total scam.

To give an example l tried my laptop in a small shopping center that had "Free Wi Fi" plastered everywhere, but when l tried it or tried it over and over, the only thing that showed a glimmer of actually working was the email, and that ended up not working either, total scam!

Fair enough that shopping centers are scared of teenagers downloading all the Harry Potter series, but slowing it down and crippling it so much that the service is virtually useless, isn't right, or may even constitute misleading advertising!

What are your experiences of this, are some places, easy access, high speed downloads, or are all public places slow and so restricted that it isn't worth trying out?

Shane

P.S. l have tried my 1 year old, defragged, and scanned for viruses Laptop before trying it out, at librarys, etc and am pretty good at getting it to work, so it isn't technical at shopping centers, they just offer a dodgy service!