Medical offices hide their numbers for very good reasons: if you've got an abusive spouse, you often don't want the medical office in your call history. Which results in a lot of very important calls being ignored.

Stopping caller ID spoofing doesn't have to mean caller ID is always enabled. You should be able to make a call with NO caller id, but not a call with somebody else's caller id.

Unless I'm missing something, this doesn't seem hard to fix: just let users decide whether hidden numbers should be ignored or received.