Shopping "basket" or "trolley"?

- the icon used on Amazon.co.uk

A curious example of where the label doesn't match the image.

I wonder...

• Is an image of a trolley easier to identify than a basket?
• Is a trolley more closely associated with shopping?
• Is it a subtle way of encouraging users to spend more and fill up their trolleys rather than a basket?!
  
• Is this merely the same as the now out-dated floppy disc representing "Save".
  
• ...or a way to avoid choosing between the British English "Trolley" and the American English "Cart"?

Well, apparently not the latter, see amazon.com(!):