TIFU by advertising for my new job the wrong way

r/

My friend recently hired me for his landscaping company (I did some under the table for for him last year). Recently I’ve been putting up door hanging advertisements that go around a door knob or handle. Earlier today I encountered a mailman(I was extremely fortunate, he’s a friend of my father) and he informed me that it can be a federal offense to put advertisements (or anything) into or on mailboxes. Some homes had closed gates with the mailboxes outside so I would put them on the mailbox. Some mailboxes were open or had a lower shelf for packages. I have put quite a few of our advertisements up on or in mailboxes (that were left open). I fixed my mistake within that neighborhood, but I’ve been placing these hangers up in at least 6-7 different neighborhoods over the last 4 days. I did a quick good search, what I did with some of our advertisements is a federal offense with a fine of $10,000. I’m extremely frustrated with myself and feeling very anxious now too. My friends business is small and he hired me on because he trusts me to work well and professionally. How fucked am I?

TLDR: I hung up advertisements on an in some mailboxes. I just got hired for my friends company.