About 5 years ago the ban on using personal electronics below 10,000 feet on U.S. flights was lifted. Now passengers can use their phones or tablets with the door closed, during taxi, and takeoff. But devices are supposed to be in airplane mode.
This is the first time I’ve heard of a real consequence for not doing that — though as a result of something that would only occur with certain airlines in Europe, the Mideast, and Asia.