Just as paper doesn't refuse ink doctors don't refuse money so if a nurse goes to their GP and looks for a sick cert they are going to get one, whether they need it or not. The real question is why nurses take so much sick leave. It doesn't matter whether it's certified or not. The notion that all certified sick leave is legitimate is nonsense. Doctors don't want to lose customers and even if they are completely ethical about giving out certs they still base their diagnosis on what the patient tells then. It isn't Star Trek, they don't have a Tricorder.
Even if there was no messing the in-built inefficiency and duplication within the system would still mean there would be gross inefficiency and waste.
Good Man! Purple. I didn't know you had such an insight to how general practitioners behave. And doctors being intimidated by nurses seeking sick certs - Is this a new type of bullying? I'd love to see any hospital management refusing a sick note signed by a GP for any member of staff. It's all about the litigation, you know! By the way, what's your source? I'm sure hospital management will be interested.