I learned about some of the postal workers vowing to continue fighting and defying the legislation. If memory serves correctly, the idea started in Calgary.
But the defiance is not prevalent in St. John's (where I live), as I saw a Canada Post truck in a parking lot at my workplace this afternoon.
The union are vowing a constitutional challenge, yet again. They did this after the 2018 strike that resulted in back-to-work legislation, and the challenge was dismissed by an Ontario judge. Wouldn't be surprising if it will be dismissed again this time around.
According to sources, Canada Post will not be accepting new mail nor new packages until Thursday. The 2018 agreement still applies and is extended to May 22.