My favorite version of this is the driving test you take in California before you get your license.
One of the rules is that you automatically fail the test if you bump a curb with your wheels. That means, when pulling into a spot, you can't inch forward until your front wheels come to rest on the curb. Fail!
At first glance it seems like a trivial thing to fail someone for. I know in normal driving, I use curbs like this all the time. On purpose, and with no hazard to myself or others.
But the fact is, you're told this explicitly up front. "Don't do this, or you fail." Given that you're warned about it—and know this is the one thing you cannot do—if you still contact the curb, then you've demonstrated that you don't know where the boundaries of your vehicle are. (Or maybe that you're not so good at comprehending instructions?)
It works as a simple filter.
(EDIT: I checked with the DMV's test criteria[0], and I don't see this mentioned in there. There's an automatic fail for driving over a curb, but it's not clear if simply contacting it counts. Not sure if my examiner was a sliderule, or if the rules have changed since I first got my license.)
One of the tests is for backing the vehicle up. In that test, you may not touch the curb. It's not otherwise obvious from the document provided that any other contact with the curb is disallowed. So either it's untrue that it's disallowed when pulling forward, or it's untrue that you know about it upfront.
Regardless, not touching the curb, even if arbitrary, can be an indicator of competence. It demonstrates control and awareness of the vehicle.
Memorizing an algorithm is a potential indicator of many things, not all positive, but I don't think it says anything at all about competence.
> ...you can't inch forward until your front wheels come to rest on the curb. ...if you still contact the curb, then you've demonstrated that you don't know where the boundaries of your vehicle are.
This demonstrates one reason why whiteboard interviews aren't great. They don't mean what people think they mean, and people think of them in very black-and-white terms. X always implies Y, or at best they say, "Well, maybe not, but..." and then justify the exact same result with only superficially different reasoning.
In your example, the driver might have demonstrated he doesn't know where the front or rear of the wheel is exactly. But it could also be he was just nervous or driving a vehicle he isn't used to using. Maybe he had to borrow his older brother's car when mom's broke down at the last minute. Saying he doesn't know where the boundaries of his vehicle are goes against all the other evidence: he didn't strike anything with the boundaries of his car. The curb is already inside those boundaries, intentionally and by design of the test.
A lot of that stuff depends on the proctor. When I took the driving test the first time in my state (not CA), he almost failed me because I failed every single left turn. Thankfully at the end he asked a question, and realized that I had done every turn incorrectly because nobody ever bothered to tell me that left turns always should go to the LEFT lane, not right.
You and half the country. The rule is actually you match the lanes left to right. Aka if two lanes are turning left into a three lane road the second from the left goes into the middle.
I suspect that people happened to have just zoned out during this part of the class, although a friend of mine recently said he was never taught that one is suppose to stay as far right as needed to allow people to pass on the left either.
And its not just random drivers, the more esoteric parts of the law (driving on the shoulder in TX, free right turns, uturn laws, center turning lane, etc) aren't even understood by many traffic enforcement officers.
In California, for a single left turn lane, you're allowed to complete the turn into any of the lanes you choose.
The driver handbook doesn't go into detail about double turn lanes that feed into a 3-lane cross street. My own rule is that only the inner lane (leftmost) must complete the turn in the matching innermost lane. The outer lane can end their turn in the #2 or #3 lane. I tend to choose the #3 lane just to put as much space between me and the car next to me, in case they incorrectly go for the #2 lane. Unless there's an opposing right-turning car that I trust less :)
One of the rules is that you automatically fail the test if you bump a curb with your wheels. That means, when pulling into a spot, you can't inch forward until your front wheels come to rest on the curb. Fail!
At first glance it seems like a trivial thing to fail someone for. I know in normal driving, I use curbs like this all the time. On purpose, and with no hazard to myself or others.
But the fact is, you're told this explicitly up front. "Don't do this, or you fail." Given that you're warned about it—and know this is the one thing you cannot do—if you still contact the curb, then you've demonstrated that you don't know where the boundaries of your vehicle are. (Or maybe that you're not so good at comprehending instructions?)
It works as a simple filter.
(EDIT: I checked with the DMV's test criteria[0], and I don't see this mentioned in there. There's an automatic fail for driving over a curb, but it's not clear if simply contacting it counts. Not sure if my examiner was a sliderule, or if the rules have changed since I first got my license.)
[0, p. 24] https://www.dmv.ca.gov/portal/uploads/2020/04/dl955.pdf