This is matches my experience, having been under at least 30 times.

The phrase:

"Why would a surgeon know anything about anesthesia risk?"

could be misleading to someone who has never undergone (or just didn't understand) what a pre-surgery anesthesiologist consult is for.

Surgeries are performed by teams. Anesthesia is one aspect of the procedure and most of the doctors know some, while surgeons know a great deal. The anesthesiologist's job, as a physician, is to monitor, adjust, and assess risk during the procedure. This disclosure, if it happened, was during the consultation.