Not if they're forced to check their phones in. I have friends working in the defence industry for whom this is something they have to deal with.

Well sites doing TS work you can sort of understand that

I knew someone who worked for the scientific civil eservice and they where not allowed to have a phone with a camera.

I have also been for an interview at a site (HMGC) where you have to hand in all electronics at reception - this was an avowed role btw so I am not breaking any laws the organisation even has job adverts on the local buses

Not even TS work - it can include lower level classifications too.