That written disclosure requirement exists precisely so a renter is not surprised by a charge they never agreed to, and it applies whether the fee is called a viewing fee, an access fee or anything else. If there is no signed agreement covering it, the renter has grounds to refuse the charge and to raise it with the Commission.
This comes up more with off-market or exclusive listings than with a home already on the Saskatchewan REALTORS Association's MLS system, since a normal listing does not typically involve any charge to view it at all. If a fee is being asked for access that would otherwise be free, that itself is worth questioning before agreeing to anything in writing.
When in doubt, ask for the fee in writing before you view anything, and confirm it is coming from a licensed brokerage. Get your hand-reviewed valuation from Joel Dyck.