I always thought that since Sony's gaming hardware is usually sold at a loss, someone like Microsoft could buy a bunch of PS3s and destroy them (or at least not use them), which would mean that Sony spent a lot of money on nothing and be driven to bankruptcy. That's very likely breaking some antitrust laws, though.
No, that's fully legal except maybe for the waste produced. In fact it's the recommended counterstrategy to dumping, buy up their stock and let them bleed dry. If Sony sells the PS3 at a loss that's their problem. Although I am surprised that selling below cost isn't illegal, it seems to fall under predatory pricing which is an antitrust issue.
Of course that strategy isn't efficient in this case as an unsold console means a bigger loss than a sold one and the additional sales would allow Sony to boast bigger numbers and get more economy of scale benefits. Sure, Sony would have to produce new consoles to replace the ones MS bought but it does drive up the demand. Sony is already scaring enough customers away, I think just sitting back and enjoying the show is enough to kill Sony.
OTOH, there are large numbers of sales for the PSP while the software doesn't sell and Sony alledgedly takes a 200$ loss per unit on those as well... Maybe Nintendo is already employing that strategy?