Had to chime in since I just went through this, twice...

I had two items up for sale on ebay, one was a car (which I was selling to
pay for my new bus --- "bus content") the other a camera.  The first time
the car didn't meet it's reserve so I offered it to the highest bidder at
their highest bid as a second chance offer and they accepted.  This time the
highest bidder on the camera never contacted me, so I offered the next
highest bidder a second chance offer, and am currently negotiating shipping
prices since they live in HI.  Neither time did I abuse the system, although
I can see how it could be done.  It seems to have worked out well for both
myself and the buyers, so I really don't have a problem with it...  YMMV...

David / NJ
Former owner of a 76 Westy (sniff, miss ya Wanda)
New owner of an 85 Westy Weekender Wolfsberg