Legit or Scam - Do they take charges just to drop off someone at airport?

Ok! So this morning, I had to drop off my father at the airport. It was just a drop off, no waiting at all. He gave me a receipt while entering. While leaving he took the receipt back and asked for ₹30. I was half sleepy probably, and of course, rushed as cars were lining us behind me. In due course, I forgot to ask for any receipt. Is this legit? I was in a four wheeler this time, I don't remember giving anything while I was on two-wheeler last time.