A similar definition might give the impression that you have some bargaining power with the Agency. If we keep the word “unreasonable”, who will be providing a definition? In your case, it's a certain noise threshold, because you have no choice, whereas to others, a different definition may apply. By forcing you to change your operating methods, we'd be back in the same situation where the most convincing arguments and negotiating team would win the day. The Agency would be bound by a definition that would tie its hands.
On October 26th, 2006. See this statement in context.