title: How do I stop Magento merging the basket on login?
body: <p>If you were to login to Magento and add some products to your basket and then leave the site, these are saved for the next time you return to the site.</p>
  <p>This, however, causes an issue when you do return. If, on your return, you added a product to your basket without logging in and then logged in at the start of the checkout process, your guest and saved basket will be merged. This is undesirable.</p>
  <p>Is there any way to make Magento clear the saved basket on login if your current basket has items in it?</p>