Personally I've always thought doing any type of logging in with any type of wireless connection would be risky. ESPECIALLY at a cafe or public hot spot. It's way too easy to eaves drop or pickup wireless signals, if I'm at a hot spot I just do web browsing and nothing that requires a login.
Of course not everyone has that luxury so just keep in mind to log in only on secure pages (https) and keep in mind things like FTP and e-mail messages are not encrypted so someone could easily read your e-mail you're sending and receiving. Finally, even if it's encrypted that doesn't mean something like this article (unencrypted cookie) can't exist and that doesn't mean someone can't unencrypted the data (although that's not as likely).
Wireless is just too easy to intercept, making it difficult to secure.
