From my perspective that sounds like a wonderful company to work in. If the rest of the business practices are as well thought out at least.

In my experience, a lot of companies fail to do proper evaluation of their candidates early on, and that creates a lot of problems down the road. That is one of the reasons why the Joel Test has the question "Do new candidates write code during their interview?" in it. Apart from making the business run better, it will probably also make the workplace much nicer for you as you will have collages who fit the company culture better.

Also, all the things you listed are directly relevant to almost any job. More so to a job in a consulting firm!

When I interviewed, there was a guy struggling with a large box outside the front door. That was part of the assessment.

If you are looking for people that do not have the "that´s not my responsibility" kind of attitude and help where needed, probably a good idea. Edit: I also don´t think this is necessarily a discrimination of people with disabilities. OP does not state you have to carry the box yourself. You can still show awareness for example ask if they need help and if you should try am get someone, as you cant do heavy lifting yourself etc.

The secretary at the front desk (Whichever one signs them in) gets asked her opinion of every candidate.

That is great in my eyes. First, you will probably encounter a lot of front desk secretaries as a consultant, as your first impression with the client. It better be a good one. Second, this is a hint to me that the company values its employees opinions and not just regard them as worker bees. *Edit because of comments: I do not get where y

For senior level positions, they will have one of the custodians or chefs bump into them and check their reaction. People fail if they get angry and calling them stupid is an automatically disqualifies type of thing.

Also great. Ever had a superior shouting at you? Not great leadership. You don´t want to hire those! Edit: Depending how it is performed, maybe a bit risky though. You should not risk hurting someone!

Sometimes the interview will start a bit late. Candidates are judged on how they react to this.

This will also be a pretty common experience when you are at a customer as a consultant. Makes sense to test if you can behave in a situation that will be fairly regular in your future!

More than half the assessment document is stuff not in the interview itself. None of these things are relevant to the job so I think they are unfair to be assessed especially since the candidates would be stressed and not on top of their social game. None of the candidates would know any of those are tests rather than just random interactions. Is this ethical? Is there someone I should report this to? I live in Canada.

In my eyes it´s fine. It should be normal and expected in an interview to be judged on a lot more than your actual technical skills and it should be no secret to anyone that soft skills are just as important technical excellence to form a good and productive team. Nothing in your example shows any discrimination, nothing seems creepy like in some other questions where the employer seems to try to peek into the private life of the candidate.

To me all you listed speaks of a boss who knows exactly what he is looking for in his company and who thought of some clever ways to find it out early on. Saves the company and the candidate the hassle of discovering a bad fit later!