First, let's keep in mind what we know about "public trust." Museums don't just think about who visits in the present day, but they also think about the future a lot. When the SCMA decides to remove an object from its collection, it has to be very careful in deciding HOW to deaccession.
Museums have to follow a precise series of steps, as outlined by the American Alliance of Museums' Code of Ethics for Museums and the Association of Art Museum Directors' Policy on Deaccessioning. These include...
1. Careful consideration and approval
2. Sale or transfer of objects
3. Purposeful use of funds
Check out these additional sources on deaccessioning in museums.