That wouldn't be a problem either. Missiles and punch-through would be bound to destroy even a single block if a player knows the general location of the force field. And if they're on the inside, then they're not being used as a second shield anyway, so it really just comes down to being used as area denial as it should be.Yes, a single block destroyed would take down the entire force field, but what if the field's modules are on the inside? This would have to be one of the problems worked out.
Can you provide a more specific example of what you mean? I feel like we might be thinking of two different things.