Keeping the cart information when login and logging out

[eluser]WanWizard[/eluser]
Do you use cookies for your session, or a database table?

I don't see real issues, providing that you delete all userdata (or any other data that relates to the user being logged in) that belongs to that user from the session when the user logs out (p.e. like user_pass, user_email, etc). I think the session_destroy() is just a very lazy way of accomplishing just that...