tipping faux pas

I think I'm a generous tipper.  Unless there is a good reason, I always tip 20% in restaurants.

I tip more for my manicurist ($2 on a $10.50 bill) and 20 to 25% to lovely Lyo, the woman who colors my hair.

And at this time of year, I tip my the paper boy (or paper man), and the building staff where I live.

Since I no longer have anyone who cleans my apartment or takes care of my son, I don't tip a housekeeper or nanny.

And since I have no private plower when it snows, or people who take care of my lawn (I have none) I don't tip these kind of service workers.

In other words, I think I tip everyone I should. 

Today I am getting my mail and see our very nice mailman. He is unlike the previous postwoman, who acted like she hated the world, and delivering other people's mail was her punishment for committing some heinous crime in a prior life.  Our new mailman is always smiling and quick to offer a friendly hello. Today he says to me, "I'd like to thank you for your very generous tip.  That was so kind of you.  I really appreciate it."

Huh?  I didn't tip my mailman.  Now I wonder if I should have.  

What do I say?  Do I take credit for someone else's generosity or do I embarrass myself and fess up.  I have no choice, really.

"I am so sorry, but that wasn't me," I tell the postman.  He asks if I'm sure.  Yes, I'm sure I tell him.  Then I add, "You are great though, but I'm sorry, that tip was not from me."

I check the government website and listed under Unacceptable Gifts for the Mailman are:

• cash
• checks
• stocks
• liquor
• anything that can be exchanged for cash
• anything of monetary value such as meals, gift certificates, and clothing.

Then this same government website adds:

Perhaps the best gift for your mailman is simply a heartfelt card saying "Thank you." (sic).

I wonder if the mail people agree.