As someone who enjoys the environment sounds in Bellisseria but also does not wish to disturb my neighbors, I find it difficult to decide whether or not to restrict object sounds to my parcel. If I restrict, then I cannot hear the environment sounds outside of my parcel. If I don't restrict, I risk disturbing my neighbors with objects within my parcel.
Solution 1: I propose an update to the Premium Homes to add an option in the Mailbox for "Sound ON" and "Sound OFF". These options would trigger a set of appropriate Environment Sound Objects that are located within the parcel that would turn on and off at the home owners discretion? But as a caution, a function in the On/Off script can check if Object Sounds are indeed restricted to the parcel so that the Environ Sounds within the parcel will only turn ON if sounds are restricted. (Because there is no reason to turn them ON within the parcel if sounds are NOT restricted to the parcel and would only cause more "noise pollution" if doubled up with the sounds outside of the parcel.)
Solution 2: Add the option to dispense an Environment Sound object to the parcel owner that they may rez themselves. This option is probably far easier to implement, but I understand LL may desire to prevent users from using the sounds elsewhere and keep Belli noises in Belli.