David Emerson, former Liberal, has defected to the Conservative Party. He will be receiving a position in Cabinet. Not surprisingly, someone brought up Belinda Stronach. There is a difference between the two, however. Emerson is not doing this the night before a vote that could topple the government. He is making his intentions known at the creation of the government.
Having said that, I still think that, if a MP wishes to cross the floor there should be a by-election. Most people vote for the party, not the individual.