I've never in my life heard of an individual person being prosecuted for violating the ban keeping a few as a pet at home. It's not like there's an inter-provincial border inspection checkpoint at the AB border, or house to house searches.
did you know about the ban in advance? Or was it a surprise when getting ready to move there? Or did the place disclose that during recruitment "FYI, no rats allowed"
I was aware, but the hiring manager thought I would be able to work from an office out of BC, however when it came down to it, in-person in Calgary was required, so I declined.
There is a dedicated 'rat patrol' as well but for the most part it's a government phone number and then reliance on citizen reporting. Penalties are fines and destruction of the animal in question.