Tipping in the drivethrough

I went to a Culver's today and haven't been in years. This location there was someone in a booth at the drive through taking orders and told us to pull into one of the spots on the side instead of going to the window to wait for our food and someone will bring it out. Well there was a very nice but loud employee she was friendly though. She then comes out with my food and is like so what's the tip of the day? I thought she was asking for advice when I said oh I can't think of one. She's like no tiiiip. I'm like oh that kind of tip. I'm like oh ok. And i said hold on my purse is in the back and she tried to open my back door to grab it! I was then like uh no ill grab it. and I gave her a couple bucks and told me to ask for her name next time. Didn't sit well with me. But part of me is like well she did bring out my food so that's why I gave her some money.

Is this new here? Is that common? I hate that this happened here i love their food but don't want to go back if they are going to be harassing me for a tip.