As I said before, I think there should be an interpretation clause to ensure that the act does not apply to labour relations and upholds fundamental rights. Otherwise, of course, it would take more than an estimate. In fact, the minister would have to demonstrate that there is an emergency.
The other issue is that goods, things and cargo are protected. Does a crate of oranges in danger on a ship fall under the security of goods? Perhaps I am exaggerating, but it could be interpreted that way. As to the right of association, I think the idea behind essential services is that the right to strike can be exercised until there is a risk to health or safety: a direct and imminent danger to public health or safety, that is, the safety of individuals, not of a crate of oranges or a Canadian Tire shipment. It is unfortunate, but strikes are an economic weapon.
I am not talking only about strikes, since many other things can happen that would lead to bargaining or arbitration. As you noted, there are very few constitutional or democratic parameters in this regard that would allow for a process during which the various stakeholders could state their case. Apart from the minister himself and a deputy minister who might take a glance at it, no one can interfere. As a result, a constitutional challenge would be needed, but the damage would already have been done.
I think an interpretation clause is really the solution; such a clause would ensure that the bill would not apply to matters of labour relations.