I didn’t go to caltech, but at Harvey Mudd we had a similar vibe. I once had a take home exam that stipulated I had to take a 5 minute break half way through the test. During the break I was not allowed to think about the exam problems. That was probably the most difficult rule I was ever asked to follow during a take-home. I tried to follow it as best I was able.

On one take home math exam I decided to TeX up my answers. This was permitted as long as you stayed within the time limits, but I forgot the command for a specific symbol. I wouldn’t be able to print my exam until after my time had elapsed, and so I wouldn’t even be able to draw the symbol on the printed exam without violating the letter of the law. Naturally using the internet to look up the command would also be a violation of the rules. I chose to just include an apology in my proof that explained the situation and then introduced a replacement symbol that I used instead.

I got the impression that most students were similarly strict about adhering to take home exam rules.