What this means is that, Imagine a customer has added a few items in the shopping cart and then gets an
emergency to attend to before finishing her checkout process. Under the current settings the session will preserve
her contents for a short period of time before it expires and looses all the cart settings.
You can disable persistent template form layout xml file
<!-- comment those lines
<block type="persistent/form_remember" name="persistent.remember.me"
<block type="core/template" name="persistent.remember.me.tooltip"