The situation where you need to wrestle is when both opponents want to grab. Western boxing is supposed to be hitting, but you still see situations where they want to hold on to each other. This is because one of them is scared. If you are scared then you will try to hold onto your opponent. It is very difficult for someone to lock or hold onto you if you know Wing Chun. You can stop the other guy holding or grabbing. If someone grabs you, you will only try to grab back if you are scared. But if you are not scared, then he cannot force you into a wrestling situation.