What is your school's policy on staff and mobiles while working?

[insancerre]

I wanted some other viewpoints before deciding what, if anything, I should do.
I work in a nursery, so our policies on using mobiles may be different to schools.
Out of the window while at work I saw a member of the after school club staff using her mobile in the playground while she was supposed to be supervising the children.
The fact that she had hidden round the corner away from any other adults made me watch her closely.
She was only on for a minute or so, but it doesn't sit well with me.
We are not allowed to use our mobiles at all while working, and they have to be locked away while we are working. Even parents are not allowed to use their mobiles whilst on the premises.
But, are schools and after school clubs the same?
I really feel I should mention it to the person who runs the after school club, as a basic safeguarding measure, not only for the children but for the member of staff.
Any thoughts?

We are more along the lines of a "have a robust policy that is enforced" rather than an outright ban. We are a girls' primary school with a nursery class.

Our staff are allowed to use their mobiles out of sight of the pupils, e.g. in the Common Room, or in the classroom after the girls have gone home for the day.

We have quite a few staff who BYOD to school for work purposes, iPads and the like.

Everyone has to sign a Responsible Use policy covering technology and internet, and of course all the KCSiE stuff.

Most schools I go to have a rule of turned to silent and in your bag, not to be used in lesson time or when you are on duty etc.
You could ask the ASC what the rule is, rather than being specific about a member of staff, were the children unsupervised whilst she nipped round the corner, or were other adults also on duty with her?
Could have been an emergency or a pressing need rather than a facebook check up, you don't really know.