I hope the question in the title lends itself to an answer. In case more clarification is required, please do not hesitate to comment below.
Some background: In Canada, an MSB is required to verify the existence of an entity when they enter into a service agreement because it is then that the MSB is required to keep a Client Information Record on the MSB which triggers the existence verification. (See last question here: https://www.fintrac-canafe.gc.ca/guidance-directives/overview-apercu/FINS/2-eng?s=7)
It seems natural to me that The Financial Transactions and Reports Analysis Centre of Canada (FINTRAC) should have a requirement of when to have a service agreement because otherwise one is under no obligation to perform the existence verification or obtain beneficial ownership which is important to prevent Money Laundering and Terrorist Financing. But I was unable to find anything on it.