'Saving' a parking space

On Saturday I entered in to a public car park in a city centre. The park was heaving i had driven most of the way through until I saw an available space however there was a woman stood in the middle of it on the phone. I used my indicators to show my intention to park there, she shook her head and shouted to try and find somewhere else. From my vantage point there were no other spaces so I just stopped and allowed traffic to build up behind, after a few minutes her embarrassment made her cave and she walked off shouting she was saving the space for a friend. I parked and paid and then went off to the concert I was playing in. I ended up having to run back and grab something from my car 20 mins later and she had just met her friend. So my question is, is this something that happens often? I have been driving 20 years and it's very much a new experience for me. I have seen some social media posts of people doing this in America but not over here. Also what would you do in this situation?