This new rule is nonsense - I see that it is to stop the lounges getting overcrowded nut I think that Diamonds at least should be aloud access what ever room they are in.
Most lounges dont get that full anyway - with most of the terms and conditions - they are written to cover hotels when there are no rooms available and upgrading is difficult. Most hotels use discression with all of the t&c - Suite upgrades are not official and indeed excluded but many of us get them from time to time. The problem with this type of management is that it leads to inconsistancy as different hotels and different staff interprite rules differently and have different levels of discression.
At the end of the day - we bring a load of business there way and they should look after us.