Door to door solicitors and door knock patterns

We have a pest control company here that routinely sends young men out, ignoring our town’s solicitation ordinance. Yesterday one came to our door

Knock knock
Knock knock knock
Ding Dong

My wife thought ringing the doorbell after the secret knock was a bit much. Then she told him he wasn’t wearing his solicitation badge (that shows the company has registered with the town) and he said, “Oh, I forgot.” Funny, he didn’t forget the Segway he was riding.