On my last WestJet flight to the U.S., on Nov 11, it was only 'collected'
during online check-in. No signature, no printed copy, nothing other than an acknowledgement button during the OLCI process.
(Other airlines - specifically Delta - have collected hard copy attestation forms for some flights, but only for those passengers who hadn't received their "Ready to Fly" clearance online in advance of arriving at the airport. Even then, though, it's been hit or miss.)
Since my last WS flight, the rules for the U.S. have changed (i.e. this week) -- so I don't know if that changed the attestation requirement or changed if/how WS might collect the forms.
And to make it more confusing, last week, WestJet also rolled out (sort of, with very confusing communication) their own online portal to get pre-flight 'travel clearance' by having COVID test results checked and verified in advance. This appears to be for all international flights - including Canada to the U.S. - but I don't know if the attestation is included in that process in any way.
https://www.azova.com/westjetswoop/before-you-begin.html?primary_resource_url_id=46131
They're using their testing partner for this online Clearance to Fly service, but the website indicates that proof of vaccination from any legit testing provider will work. There's just an extra "test result confirmation service" required for those who didn't book their test through Azova, or who didn't use one of the Azova home kits. From their
press release on this new clearance tool:
“Once you have received your test results, enter your AZOVA Credential ID into the AZOVA WestJet and Swoop site and receive a travel clearance on the AZOVA app for your destination. You can simply show your travel clearance at the gate with no paperwork and no confusing forms required.”
It seems odd that this "clearance to fly" process and tool were buried in a press release about selling do-it-yourself COVID tests, and there's been absolutely no other communication or mention of it since. I don't know if it's up-and-running yet, if it's mandatory versus optional for passengers, or - if optional - if there are benefits to passengers who use it rather than just show up with paper reporting of their COVID test results.