If instructors are testing implementation details on paper exams then they're really missing the point of CS education. Completely lazy and incompetent, should be terminated.
Some portion of computer science education needs to be practical (implementation details), while some portion needs to be pure computer science (pseudo code).
Obviously projects are a good way to measure implementation details, but they are too easily cheated. Every class I took had exams as 80% or more of the grade. Not every class expected accurate syntax on exams, but most expected code rather than pseudo code (typically C).
Quite literally an "implementation detail."