The Airbus above is venting not leaking.
All aircraft have a leakage schedule. There is no grey area eather mil or civvy. Any Air Eng/Flight Eng or Pilot worth his salt wouldn't take an unservicable aircraft. We need to be very careful with terms like "Leaking like a sieve". Some do but it's within design limits. Others may be outside limits. Thats why both ground and flight crew are trained to recognise and asses leaks and should know what the limits are or how to find them.