I got a note and I followed it up with a question to my cousin, who’d worked for his dad’s campaign: and the answer was, if it arrived in the mail, the hat would go straight in the trash, he was afraid.
So it would need to be delivered at a meet-your-Congressperson event. That’s not news I want to deliver, but it seems to be a much better idea than trusting the mail and wondering. And it does get the message across on an even more personal level.