I could provide some ideas related to foreign workers and the role that CBSA plays in providing validation inspections of potential foreign workers.
Are people working extended hours? Are work sites cordoned off? Are people not allowed to talk to the public? Are they working weekends? Are there children who are not going to school? There are a variety of different indicators. There's a lot of information available publicly.
If I could maybe finish with this, there is a human trafficking hotline. It's 1-833-900-1010, and if anyone ever has any questions, you can call 1-833-900-1010 and can certainly secure more information. You'll have dedicated expertise to support you and to potentially provide things that you could look for, as well as which police of jurisdiction you might want to refer the issue to.