I have a 2020 prime XLE and I’ve used the trigger lock function without issue. At gas stations without the trigger lock I’ve wedged my gas cap into the gas filler gun thing then sat in the car while it filled until it clicked. No issues here. The white plastic in the Prius gas neck area did cause me to do a double take the first time I noticed it. I actually think it works much better than the ‘07 I had for years and the bladder system. I feel like I’m actually filling my whole tank, not 80% of it.
You shouldn't get back into the car while filling. More a problem when cold and dry, you could build up a static charge while doing so, which is enough to ignite gas fumes around the filler.
But if you do get back into the car, you must discharge that new static charge (created when again exiting the car seat) somewhere safe (e.g. on the driver door) before approaching the gas nozzle. Some long ago threads here have video of static-spark-induced flash fires caught on surveillance cameras, ignited in exactly this scenario.
I think one of the minor annoyances of living up north in the winter was getting shocked almost every time I got out of the car. I learned to reduce the big snap by getting out and thumping the outside of the door with the pinky side of my fist, Not sure if the speed of the contact reduced the intensity of the spark or if the thump was just a distraction, but it made a difference I could feel. I would never get back in the car while fueling just for that reason, especially in the winter.
