There are several versions but that’s a 3 2 , ideally your trying to create a turnover inside the zone.
If that a 3-2, then so is having three forwards between the blue line and the red line.
Yes you are trying to create a turnover in the neutral zone — by forcing the breakout to one side or the other, then trapping the puck carrier before he can reach the red line. Without a forechecker, there’s no pressure on the puck carrier and therefore no reason he would skate into the trap. One drop pass and a trailing man can go right up the middle of the ice.
If you don’t believe me how the trap works after seeing a 6-minute video describing it in detail, I don’t know what to tell you. Yes it is technically possible to run a “trap” entirely within the neutral zone, but that is not what people are talking about.
Edit: more to the point, you said there
cannot be a forechecker on the neutral zone trap, that all defenders
must be in the neutral zone. That’s just not accurate.