The Ghost of Snapped Shot

hehehee.. SNARK. 

But, why not?  Hook up a line to the legs of shoppers in order to DOUBLE the energy production?  Then also connect a pulley system to the kids so that when they run off and then back, that generates kinetic energy as well?

Oh, don't forget to add those windmills on to the handles so you can generate power just by walking through the air too.

Or...or.. or.. how about magnetic zones in the basket.  That way, when you place oppositely charged products IN the basket it will cause the electrons to flux, thus creating a flow of energy.  THen when you pull the items OUT of the cart, there is an additional flux of energy that can be harnessed.

Or, why not just charge for the use of the cart like they do in airports?

Nah, that would be... ... simple.