Emergency contact is usually people with parental responsibility?! So what would the parent say if called?! Sorry can’t be bothered?!
I'm trying not to give specifics here because of how outing it would be, but you honestly have no idea of how some parents behave.
In many cases, as I mentioned above parents will name an obliging granny or some other relative if both parents are working. Only when we cannot get hold of the named contact do we then contact the parent. (I can only speak for my own LA.)
When it comes to behavioural problems, there are some parents who simply switch off their phones so that the school cannot reach them.
In the case of the parent I mentioned above, we couldn't get through on their mobile, so in the end I got our office to contact the office at their place of work as a last resort. I figured that any normal parent would wish to be informed. I figured wrong.
As I said in my pp, it was actually a medical emergency. I'm assuming from how irate the parent was that they didn't believe that their child (a senior pupil) was actually unwell, but we couldn't take that risk.
They had three children at our school, and I'm only aware of that parent being contacted at work on that one occasion.
Most parents, however, behave in a much more normal manner.