Does this answer your question?
Yes, there must be an averaging agreement that covers all employees who work in Alberta, even those whose work in SK would be covered by an agreement in that province.
The good news is that so long as the employer meets the requirements of the Alberta legislation, employees who work in Alberta are subject to such an averaging agreement on 2 weeks written notice, or if it is part of the terms and conditions of employment on hire. Employee consent is not required.