괘씸한 매니지먼트에게 알리지 않고 서블렛 줘도 괜찮을까요?

.. 204.***.60.2

Better not. If you break the rule (sublease without consent), they would blame this for any reason. Then the argument is not that they did not respond, but that you break the rule.
Do not give them a chance to blame anything that they try to cover their fault with.