Whether they're exempt or not... abusing it can get out of hand.
Salary is based on "full time" scheduling.
If your salary is $30,000 a year, that's about $14 an hour. They would expect you to work on average of 40 hours a week. Of course, there will be times when there are emergency projects or deadlines... so some people work extra. Then there's also when they completed a huge project and get to leave early. Either way, the overall average is about 40 hours a week.
The problem with EA was that they were forcing their employees to work extra hours plus weekends.
