If found untrue, I expect the National Post will fire Ivison over this tweet.
Keep in mind that it was Ivison who spread the rumour that Harper would resign after returning from Israel earlier this year. (see here)
Update: Ivison goes full-TMZ and posts a column on this rumour (see here)
h/t Rob Rheaume
Update: The National Post’s management has swept this all under the carpet. First they changed the headline to now say “Prostitutes back off exposing Conservatives clients” and allow Ivison to include the tweet above but omit detail that it was sent to him 12 hours before it was posted (see here)