Mom's who chose to wait

Hey for the mommies that chose to wait till birth to find out gender how did you go about ensuring the practitioners didnt tell you or see accidentally during ultrasounds?

My anatomical ultrasound is coming in a week and Ive decided to let miracles be miracles and wait till birth, but im concerned my doc might slip or the ultrasound tech will say it out loud anyways.

Ive got 23wks or less left to keep it unknown. I need suggestions and then encouragement.