Gcmsnow.com is a private agency that helps you get gcms/cbsa notes if you do not have anyone in Canada that you can have it done by.Are you sure the link is correct? I googled CBSA notes but came up with different site: https://www.cbsa-asfc.gc.ca/agency-agence/reports-rapports/pia-efvp/atip-aiprp/req-dem-info-eng.html I am confused. Thank you
Basically, when you get Gcms or cbsa notes you use Canada's Access to Information Privacy Act. And only people in Cananda or Canadian Citizens can order this. So if you are not there and have no one in Cananda who can do it on your behalf, you hire agencies like these.
My friend @ts270890 sent you that link because he thought it is well explained there.