Students in general are wary of being tricked by teachers.

High school students in general believe teachers are out to make them fail as opposed to helping them.

Also, freshman students are idiots, as you've pointed out. This is due to a combination of puberty and a misplaced feeling of adultness. Freshman think that because they're in the big leagues in terms of high school, that they're adults. This concept occupies most of their time thinking when they could/should be reading directions.

While your intentions were genuine, high school students are forever skeptics. They think "there's no way it could be that easy."


But generally they're arrogant pricks who think they know everything and don't need to read the fucking directions.

Also, boobs are important. Most of your male students are contemplating the female classmates anatomy as opposed to caring about your test.

Most of your female students are contemplating how they look and are too busy with their vanity to consider your test.

I'm now too busy thinking about boobs to care about this question.