I almost sat on someone’s lap myself!
I had left my jacket on the chair and my Megillah on the table so that it should have been obvious that seat was taken. I returned after three minutes and found someone sitting there and my Megillah open. There were no empty seats, so I just asked if I could share her Megillah. She said, “Sure, but hopefully the person it belongs to won’t come.” I smiled and said, “Here’s an extra Megillah. She lets you keep the seat.”
This wasn’t a power struggle as she would’ve relinquished the seat. I just feel good that I let it go.