My whole life, the story has been something like "the PM/Party brain-trust thinks person "X" would be great in cabinet (they rarely are), so a seat that has reliably voted for the party since before electricity has its' current member (who most people even in the riding can't name) resign to go into the senate, thus creating a "by-election", and allowing for said star to ascent to the heavens of Parliament..."

I grew up in a "safe seat", and having a nobody had a double whammy. We neither received the spoils of being in government (why should we? - we didn't need to be directly bought), and when our members' party was not in government (rarely, since they were Liberal), we experienced the closest thing to living on Mars on this planet - having a non-entity MP sit in the opposition...