Is tipping at your favourite restaurant good PR?

What principle of persuasion did tipping follow?

Was it:

A) Identification principle - What was in it for the waitress if I ordered?
But the tip came after the good service, tipping was never disclosed before the service was done... So what was in it for you waitress? Nothing. At least not until I get my food.

B) Action principle - Did I make it easy for waitress to agree to allow me to put in a late order?
Again, the tip came after and you didn't use the tip to make the waitress put in the food order. The only action I could have done was told her I was outside the restaurant ready to pick up my order once it was ready. Another thing I could have told her was that I was ready to pay with cash, making the transaction quick and easy. But none of these have anything to do with tipping.

C) Clarity principle - Was my request clear to understand?
I think it was pretty clear to the waitress that I was being an annoying customer that wasn't respecting their business hours.

or was it

D) Familiarity and Trust - the use of a reputable symbol, object, brand, or person.
I didn't tell the waitress Mayor Katz was the person that was going to eat the pancit. So she knew that I wasn't some celebrity that she needed to extend special treatment to.

Now here was my argument:

My dad was down with the flu and was wanting Filipino food from one of our family's favourite restaurants. I got his voicemail to pick up some food at 6:56 p.m. so by the time I called the restaurant to order pick up, it was 7 p.m. - exactly when they closed. Sure enough the lady answered and said they had already closed. I asked nicely and told her my dad wasn't feeling well and wanted their famous noodles (pancit (PAN-sit) - Filipino noodle stir fry). She said they were closed and I asked if there was pancit left over as I knew they cooked them in big woks. She hesitated, apologized, and paused, as if reconsidering if she would still allow me to order food. Again, I asked nicely and inserted another please in her silent pause. She agreed and got one of the cooks to prepare an order of pancit for me. Sweet!

When I got home, I was [almost] attacked when I told the story of how I got the pancit and the amount of tip I left the nice lady at the counter. The pancit order came up to $9.97 after taxes and left a $5 tip. In the States, a 20 per cent tip was considered a "good tip" by TripAdvisor. I tipped her 50 per cent and my parents said that was too much.

Now here was my reasoning and I hope you agree:

A 20 per cent tip would have been $1.99, let's say $2. So I told my parents what's an extra $3 to show that I really appreciated them taking my order after they closed. I didn't mention that I had to wait a bit because they cooked my order fresh!

So my argument was: for an extra $3 dollars ($2 tip was a given), I showed the staff that their efforts were appreciated. Actually, they asked for your name for pick up orders. The first thing the owner said when I walked into the restaurant was "Oh, so you're Emmanuel." Because I left a pretty good tip, she'll remember me as a customer and I'm sure if this were to happen again, they wouldn't hesitate extending me the same customer service once again. Now wasn't that $3 well spent? I thought so!