BE KIND

I walked into the first gallery, took a seat and waited for the presentation to begin. A lady tapped me and tersely said, “Excuse me. I was saving these seats next to me. That’s why I put my stuff down. One, two, three. Maybe you can sit over there. There’s an empty seat over there. These are taken.” 
I smiled, said “No problem, ma’am”, and relocated myself to a cozy corner. She  humphed, folded her arms and continued to play sentry. The director walked in, introduced herself, greeted and welcomed everyone, then said, “We’re glad to have our featured artist here with us today...” I smiled and waved. 
You know the rest of the story. 
Lol...

Demonstrate kindness and consideration to everyone... all of the time. That will eliminate the need for awkward apologies. You don’t have to know who a person is, and it shouldn’t be necessary for them to defend their right to be, identify, qualify or explain themselves. Just be kind. 
Besides, backpedaling is hard and it’s really hard to get egg off of your face.
Lol...