I don't know what people are surprised about. If there wasn't more ignorance than people having even a passing knowledge about the British immigration system, articles like this wouldn't have an audience.
Sure, it's someone's responsibility to know what the immigration rules are before trying to use them, but to be fair, it's a lot of people's responsibility to know immigration rules before they do things. For instance, before moaning and whinging about immigrants. Before calling for the legislation to be changed. Before voting for a party based on their stance on immigration (and to even assume you understand the parties' stances on immigration...or to assume that most of the MPs understand the laws). Before asking the Prime Minister of the UK where all the Eastern Europeans are flocking from. And so on.
I don't think that it's unfair that she might have to leave any more than it's unfair that people spend years trying to make sure they are with their husbands and wives the right way. I do feel for them, as I do anyone else caught up in immigration bureaucracy, ignorant and partially victims of their own ignorance or not.