I was waiting in line for a wilderness permit in Yosemite, and one fellow was two in front of me. Then the ranger asked if he had a bear canister, and he said that he did. The ranger asked which one, and the fellow could not spit out any brand name, so the ranger told him to bring it into the permit station to be inspected. The fellow got it out of his car trunk and brought it in. He had a big rectangular Tuppermaid box covered in a few directions with duct tape. The ranger almost laughed, and refused to issue him any permit with that contraption. The ranger had a rental canister, but the fellow would not cough up the $5 or whatever to rent it. Instead, he just left without any permit. However, the ranger already knew where he was going, so she radioed over to the trail patrol rangers to be on the lookout for him and to have their citation book ready.
I had my food inside my bear canister inside my pack. So, when I mentioned the brand of bear canister that she did not recognize, she wanted to inspect it. I flopped my pack out onto the floor and pointed to mid-way where the bear canister was (inside). She simply rapped her knuckles on it, and when she heard that solid thump, she said it was OK.