Edit: Lol, there's literally nothing wrong with this observation. HN has truly gone down the gutter. I know not everybody here is part of the hivemind but the few that are completely spoil the experience for everybody else.
> Canadian authorities told her to go back to the US and fill in new paperwork before returning to cross into Canada.
If it's not mistake, and the article is complete, it sounds like the reporter skipped some important details about what Canada did. Hopefully an honest mistake.
> She was planning to stay with a host family where she would carry out domestic chores in exchange for accommodation and was told she should have applied for a working visa, instead of a tourist visa
She probably told the Canadian border that was her plan in Canada as well and told her she needs a work visa. Basically like a live in house keeper.