Dash8400: Having a poison pill is ALWAYS a good idea.....you don't have to use it and potential suitors will not be easily scared away.
I had wondered the same when the poison pill we once had was not renewed a few years ago. But it turned out that a regulation had been introduced in Canadian legislation that made takeovers difficult and thus made an explicit poison pill unnecessary. I don't remember the details, but I know that I was very happy with that.