I spent 10 years at bargaining tables in my work career with the private and public sector workers Manitoba. I can tell you that not every employer is going to use scabs but those who do will indicate that pretty much on day one of bargaining. They will make that indication by the kinds of proposals that they table and by the attitude that they bring to the bargaining table about whether they are seriously looking at your proposals. They will be looking at tabling very aggressive proposals. Also, they will be looking to incite that situation rather than coming to the table to actually collectively discuss the issues at hand in a meaningful way to find a fair and reasonable resolve. Whether there's a mediator involved or not, it doesn't much matter if an employer is not prepared to actually come and fairly bargain a collective agreement.
By having the opportunity to continue to operate while there's an ongoing strike there's always going to be an imbalance because that means that there's no need for that employer to come to the bargaining table with the actual intent of reaching that collective agreement.