The way the law is written there is no grey area. It clearly states that the only legal method for hunting turkeys in both the spring and fall is by calling.
However, I will agree that it is highly unlikely any WCO wold cite you for waiting to ambush a turkey while sitting on a stump. However, I think it might be an entirely different story if a WCO and his son were calling to turkeys and you moved into that area and shot one of the birds they were calling. That would be a classic case of stalking which is what the law is intended to prevent.