It's a bidders game

But what if everyone's bidding? Whose game is it then? Generally the last person to make a guess loses, here's a hand:

♠	Q J 8 6 5 4 2
♥	K J
♦	T 8 7
♣	3

You're third in chair at nil vul and you're playing for IMPs rather than matchpoints. You watch the following auction:

North	East	You	West
1♦	X	1♠	4♥
Pass	Pass	?

How many points do you think you have between the two hands? We're told that 4♠ over 4♥ is right almost always, is there any reason to expect something else here? There's some chance that both games make and there's a good chance that both games fail; if that's the concern 4♠ is the bid. I thought it was a pretty clear action; any voices of dissent? What about when East doubles? Doubt creeping into anyone's mind?

Vul: Nil Dealer: N	♠ - ♥ 6 4 2 ♦ A K Q J 9 5 4 ♣ A 8 2
♠ A 9 ♥ T 9 7 5 3 ♦ 6 ♣ Q J T 7 5		♠ K T 7 3 ♥ A Q 8 ♦ 3 2 ♣ K 9 6 4
	♠ Q J 8 6 5 4 2 ♥ K J ♦ T 8 7 ♣ 3

Turns out both 4♥ and 4♠ fail, the former only if North gets a spade ruff but the later can't avoid three trumps and a heart. I'm sure you've noticed though that none of that matters when you're losing a stack of IMPs to 5♦. West has taken a wild action here but in doing so ensured that he's not last to guess.