It's only employees who have managerial roles (which means the authority to make high-level decisions, like about hiring and firing), specialized professional skills, or something of that sort who are exempt from the requirement to be paid for every hour they work.
http://www.flsa.com/coverage.htmlWith few exceptions, to be exempt an employee must (a) be paid at least $23,600 per year ($455 per week), and (b) be paid on a salary basis, and also (c) perform exempt job duties. These requirements are outlined in the FLSA Regulations (promulgated by the U.S. Department of Labor). Most employees must meet all three "tests" to be exempt. . . .
An employee who meets the salary level tests and also the salary basis tests is exempt only if s/he also performs exempt job duties. These FLSA exemptions are limited to employees who perform relatively high-level work. . . . There are three typical categories of exempt job duties, called "executive," "professional," and "administrative."
Job duties are exempt executive job duties if the employee
1. regularly supervises two or more other employees, and also
2. has management as the primary duty of the position, and also,
3. has some genuine input into the job status of other employees (such as hiring, firing, promotions, or assignments). . . .
The job duties of the traditional "learned professions" are exempt. These include lawyers, doctors, dentists, teachers, architects, clergy. . . . Professionally exempt work means work which is predominantly intellectual, requires specialized education, and involves the exercise of discretion and judgment. . . .
The most elusive and imprecise of the definitions of exempt job duties is for exempt "administrative" job duties.
The Regulatory definition provides that exempt administrative job duties are
(a) office or nonmanual work, which is
(b) directly related to management or general business operations of the employer or the employer's customers, and
(c) a primary component of which involves the exercise of independent judgment and discretion about
(d) matters of significance. . . .
To be exempt under the administrative exemption, the "staff" or "support" work must be office or nonmanual, and must be for matters of significance. Clerical employees perform office or nonmanual support work but are not administratively exempt.