According to the article, they aren't staying in jail for long.

> "Once that we do all our checks and that we can confirm that they're not a threat to national security, we hand them over to [the Canadian Border Service Agency] who then start the immigration process," Habel says.

Does "immigration process" mean deportation or admission?

> officials with the CBSA say that if they determine that she isn't a danger of a flight risk, the agency will release her and her baby. It's then up to a tribunal to evaluate her candidacy for refugee status.

I don't specifically know about Canada but in general the refugee application takes some time. They have to be assessed if they are genuine refugees (like leaving war or political/personal persecution) and either be given status (admitted) or deported.

Yeah I'd like to know too. If they're deporting them, then why aren't people upset if/when the US does this as well?

If not, can I just walk across the border, hang out in jail, then become a Canadian?

If you've got a legitimate refugee claim have at it.