I think that's the whole idea behind these being puzzles --- someone who uses syntax highlighting as a sort of crutch will stumble over these, while those who are actually looking at the characters won't. One of the other ones does something similar with a comment, and it made me giggle a little as I caught it immediately. It's somewhat similar to a https://en.wikipedia.org/wiki/Stroop_effect experiment.

I bet even more would be confused if the 'defa1ut' one said 'defau1t' --- showing how font choice can also be very important to readability.