A:

It doesn't. Philosophically, RAD has never been a big fan of handling sound prioritization at the library level. The way Miles works, the application can just allocate sample handles until it hits the system-imposed limit. The application is then responsible for reusing those handles in whatever way it sees fit. You can use whatever criteria you wish to bump playing sounds (age, importance, distance, volume, the existence of duplicates, etc.), or decide not to bump any at all if the new sound isn't that important.

A lot of that flexibility goes away, or becomes awkward to access, if you make Miles responsible for killing existing sounds in favor of new ones.