Mobile telephones are banned in my school.
I understand why. They can get broken, stolen, be used for bullying, disrupting lessons, etc, and if a student doesn't have the "right phone" then that can be a basis for bullying, too.
Two weeks ago, I was teaching a Year 11 (Grade 10) GCSE French class when I noticed one of the students using a mobile 'phone.
I asked her what she was doing.
She replied, "I'm using "wordreference"to look up a word I can't find in the dictionary."
She showed me the screen and, sure enough, she was.
I was pleased. A student taking responsibility for her own learning is a rarity in my school and I praised her for using her initiative.
Some of the other students were amazed that I didn't confiscate it, like some of my colleagues would have.
Now, if they ask, "Can I use my 'phone to...?" even though it is against the rules, I usually find myself saying, "Yes."