The rules are strict. Take a look at what happened regarding those volunteering after the Tsunami. As much as people are genuinely trying to help, there would always be those that would take advantage if the authority's simply allowed it to happen.
I have no idea how they can fine you in that case. I've never heard of needing too notify the immigration office in the province you are leaving that you won't be residing in that province any longer. Saying that though, nothing surprises me anymore.
The passport is swiped like all UK passports are swiped. Do you think they don't know if a UK passport holder is walking in and out of the country? Of course they know who's going in and out.
They know you've left. It's on the system but your passport isn't stamped. I'm stamped into the US on a UK passport but never stamped out. They of course know I've left though.