I recently had a NPB on a MH auction. The winning bidder was international (Brazil). After six days of no communication or payment (I did send a couple invoices and a message), I opened a NPB on them. That got their attention, and they messaged me stating that the cost of shipping was too high compared to the cost of the item, and that they no longer wanted the item. Now, I clearly stated in the auction that while I did accept international bidders, the cost of shipping might be high and to please message me if they wanted to verify the shipping to their country (since sometimes the automated Ebay shipping thing is incorrect).
I would have had no problem had they bid, then realized the cost and contacted me. But since they just decided to ignore me until Ebay got involved, I will be blocking them from all future auctions of mine. They have 100% positive feedback (with 135 transactions), so they may slip underneath the radar. And we all know Ebay rarely penalizes bad buyers/time wasters.