I always go before I get on the plane. This woman probably played with her phone right up until it was time to board. Then she ‘has’ to pee.
I fly frequently. The last thing I do before I get on a plane is use the restroom by the gate. I hate plane bathrooms. I’m always amazed that as soon as I get set down people are lining up for the bathrooms. Then as soon as the seatbelt sign goes off they start again. It’s like when I used to take my daughter somewhere and she always had to use the restroom in every place we went.
I really try to avoid public bathrooms as much as I can.