Purser@AC maybe you can answer more fully why some I/C's still rip off the small portion of the boarding card as I've noticed this discrepancy too. And you're right; all the information you could need or use is on the final manifest.

I've had customers board presenting their boarding card with the separation of the perforated card thoughtfully started. They are then quite surprised when I don't finish the job and keep the stub.

For J class I will often pull the stub to put on the hanger with the customer's coat or jacket but other than that, it doesn't get pulled.

An explanation for some of the cases where "now they do, now they don't" could be accredited to the origin of the crew. Both AC and CP metal operate flights into the same cities, but at different times of the day. No former CP crew will pull the stubs - we've never been instructed to, but an original AC crew might due to past practice.

I see this inconsistency often on the eastern Rapidair flights where the operation is split between the two fleets. AC metal pulls (sometimes), CP doesn't.

Maybe it's time to bring this to the attention of the customer service or inflight department so that steps can be taken to put us all on the same page.