When you are sitting in Starbucks and using their, or any other public wireless connecdtion you are open to attack.
Small Business Pipeline writes Using public Wi-Fi is perfectly safe, as long as you’re careful what you do, pay attention to making your computer secure from wireless sniffing and over-the-shoulder peepers, and be careful where you browse. In fact, it’s probably a lot safer than using an ATM at night, and chances are you already do that every week.
To protect yourself the article advises that you use a VPN, personal firewall and encrypt your logon/password. Read the full article here