Sorry, but the flip side of this argument is to enforce every SE have bag tags and carry their card with them, displaying it at all times to receive perks; no card, no perks. I have witness the rudeness of YYZ ground staff on many occasions, but I find it to be consistent across the board. Part of me is glad that AC staff check the lines and priority checkin areas to ensure that those in line and in those zones are 'entitled' to be there.
Most of my flights are ULH so I'm leaving Sunday's between 10am and 3PM, I'm usually in ripped jeans and a t-shirt, I'm typically treated with respect once in the designated "Elite" areas. On occasion I'll be questioned about my status, I'm ok with that, even if it requires me showing my BP or card, most of those times they'll catch at least a few people intentionally, or unintentionally getting in line or into the priority sections. Is it really that much of an inconvenience? to me travel is the big inconvenience; in fact, I wish they did it more checking in priority boarding lines and checkin lines where they don't have designated priority sections.