It's definitely not what people are doing. Even as Mt Gox showed, people will just leave it where it's convenient. And for a lot of common users, they probably

It's definitely not what people are doing. Even as Mt Gox showed, people will just leave it where it's convenient. And for a lot of common users, they probably ARE a lot better off with their coins existing as a row in Coinbase's MongoDB database than as a file on their PC. And I say this as someone that dislikes Coinbase and was burned by them (one day they seized all my coins until I verified ID on login, then erased my bank account connections and refused to delete my PII that I only provided to withdraw my coins in the first place.)