There’s a lot of outsourcing already. In Ontario, Amazon does most (all?) of their deliveries with generic white vans operated by independent drivers. The goods do typically come from an Amazon owned warehouse.
Apparently - Amazon owns none of the Quebec warehouses - they are all leased.
That’s because they aren’t! Wow, union busting on a vicious level! 
Feds post letter on X, upset about decision. Premier of Quebec, a major business leader before politics, says it was regrettable but a management decision by a business .
Doesn’t matter if Amazon owns or leases. It’s the business operation as a whole that is subject to the union certification. But if Amazon truly transfers the lease to some other business, then the warehouse would likely no longer be included in the certification.
Some analysis here:
Op-ed from a Manitoba labour law professor:
Reports that Amazon’s delivery times in Quebec are lagging.
Add to that a general feeling of boycotting American companies and Amazon may have shot itself in the foot.
In the US, there are a few alternatives to Amazon, like Walmart, which can supply many of the same goods. Are there similar alternatives in Canada?
No one has quite the variety and speed of fulfillment. Walmart has a lot of 3rd party sellers but they all depend on other delivery companies.
BC Labour Relations Board has certified Unifor as bargaining union for an Amazon store. Amazon says they will appeal.
Heard on the local news last night, Amazon is building a new warehouse in Ottawa south, they said the biggest yet in Canada, wonder if it’s to cover Quebec.
Bit more detail on the BC certification:
Canadian labour law is generally that the employer is to stay out of à union drive and leave it to the employees.
I’ve not seen the decision, but based on this news item, sounds like the board concluded that Amazon breached that rule.
If that’s the issue, I think Amazon will have an uphill battle on judicial review. That’s the sort of workplace assessment that’s squarely within the board’s jurisdiction.
I think you’re right. The entire point of setting up such labour relations boards was to keep such matters out of the courts. And BC has an NDP government that is not particularly “labour friendly” but knows this certification is big and important to labour, from which the party gets some support.