Flash works but it uses the default system connection and not your browsers proxy connection. So in cases of site that have IP based restriction, flash based sites will still see your original IP
and how do you know about this ?
I use the very same trick with youtube and many other flash based sites.
And flash ALWAYS use the browser's settings (at least in opera and firefox) both in Windows and Ubuntu
- watch Hulu, when you're not in the US
- use Spotify when you are in the US (and you use a UK box for example)
- bypass your university firewall
- in general secure your connection in case you are using an open network