I was under the impression that air traffic controllers could suppress signals from planes squawking 1200 to avoid clutter on their screen.
As a private pilot, I have had my transmission swamped by another plane transmitting on the same frequency at the same time. I'm told commercial planes have stronger transmitters.
Yes, I have been refused clearance through controlled airspace. I have no problem with this.
If it is an emergency, say so, or act accordingly regardless of permission.
If you look to the left, I was taught, "See and avoid."
the pilot reported that he was operating in clear conditions,
Not the sort of comment that would indicate an emergency...