So now you have this hand. What is 3c? Normally, it should show something like 16-18 with 6+ clubs and be invitational to game. With the interference, however, a lot of people like to play this as just "competitive", which to a number of people is synonymous with minimal (I hate defending). You know you are going to bid spades, but 3 or 4? 4 would tend to kill the auction destroying any chance of getting to a slam, but is 3 forcing? Without the interference, how many would play 3s as forcing?
I was asked about this hand and I suggested the auction above, which is what they did, was correct. 3c should show a quality hand. Maybe not the 16 count needed without the interference, but might be shaded with heart shortness. I got the response of, "Well, we actually just play it as competitive, but I didn't know what to do with it". Their partner then bid 3s, which they both agree was weak. East didn't want to overbid in case partner was a minimum, and west didn't want to bury a partner with 4 points. 3s making 5.
8 out of 18 who played this failed to reach the easy 4s game.
Now, some NS pairs may have bid 1h-3h, I'm not sure how that changed things. Even with the preempt, it shouldn't be too difficult to get to 4s. The whole point of this, is that the lack of disciple in bidding has caused all these questions on how good hands are that bid at higher levels. I admit that if the opponents execute a preempt, you may be forced into guessing how high to go. These kind of scenarios should be easy, however. You just have to have the discipline to pass the 2h bid with minimal hands. Once partner knows that you have a good hand, it gets easy. Then on the flip side, the 3s bid should be forcing and forward going. You need the discipline to pass 3c with 6(or 7) spades and a lousy hand. Yes, it may actually make 3s and be the superior contract. I think it's better to have a constructive meaning to the bid than force partner to guess what in the world you have.
See you when I spot my next windmill.