At one time it was. The condition things are now. I don’t know. And it was a nono to put the flag up whit no mail in the box. I know that because when I was young some friends where playing in the front yard and decided just for fun put yje flag on the mailbox up to get the mail man to stop.He stopped and was not amused. He turned the motor of his car off, got out of his car, walked to the front porch, went up the steps and knocked ob the front screen door. Mama came to the door. He talked with her for a minute and left. Mama walked off the porch went over to an oak tree, broke a limb off for a switch, called to her and wore my butt out right there in front of all the kids.
“And it was a nono to put the flag up whit no mail in the box.”
No worries - they leave the flag down and tuck the flyer between the flag and the side of the mailbox. I don’t believe anyone has faced repercussions for doing that, so it’s probably OK.
Local kids who want to pick up pocket money doing yard and farm work on their summer vacations put out these flyers and we’ve hired some good help that way!