Yes, the standard instructions say to report all post secondary institutions enrolled in or where courses were ATTEMPTED.
They can check because about 93% of all schools in the U.S. are contracted with the National Student Clearinghouse which is a private company that acts as a legal "agent working on behalf of the college or university" (see FERPA) and stores your records from the colleges you attended and also retrieves them for admissions officers.
So, because 93% of all schools just happen to use this one system it kind of acts like a central database, even though each school has individually authorized NSCH to act as an agent.
This way, NSCH is allowed to grab your stored records and disclose them electronically through a computer to the admissions office of the college you're applying to.
I can't tell what the procedures are of each admissions office is though.
But if they say you have to report it and send a transcript, then you have to.