I had this going into AMS from LCY once due to terrible visibility. The lady next to me seemed oblivious and I was nervous (too British) about nudging her. After a minute or so of internal struggle I did point it out politely and she was so effusive in her thanks to me (no sarcasm), immediately turning off her phone, that I was glad.
I'm happy it's just an over precaution but I like those in air travel!