I welcome the discussion but I’m not sure I follow your train of thought here, could you elaborate please?
Assuming that “shooting from the grey zone” means enemy tanks camping in an area inaccessible to your team (out of current map bounds), you have to keep in mind the grey area differs from between teams. While the tank is to you in a grey area, from its perspective it is within map bounds.
Furthermore, any tank that gets close to infantry is a “dead” tank and is a bad tactic to begin with, making tanks nearly useless. It’s pretty bad on Berlin for tankers