An easy 3♠  preempt for East
South will probably pass with 12HCPs and short ♣ s
West has a difficult decision whether to raise to the leval of fit or pass. Vulnerable will scare people off, but it might stop a slam. The key question is will you bid 4♠  if they get to 4♥ s? If so bid 4♠ s.
If West passes N will double and South will bid 4♥ s. If North passes - this is forcing as N/S are in game. South being balanced and some ♠ s he will pass.
If West bids 4♠ s, North will still double and give south the difficult decision of whether to pass or bid 5♥ s, being balanced South will probably pass.
Those going for -800 in 4♠ s doubled will be poor this time, but it may have stopped N/S finding the 6♥  or 7♦  slams.
To find the slams is not easy over 3♠ s.