What if you are exempt?

My employer sends me home at night sometimes and alleges that it is doing so that it doesn't "burn out" the employees. Even though it does not cost them any more to keep me for the extra 3-4 hours.

Can I refuse to go?

Yes you can refuse, and you could be fired (legally) for it. It's called insubordination. Your employer is looking out for your best interests and trying to give you a life-work balance. Appreciate it.

Please do not attach your question to someone else's thread, especially one that is three years old.

Yes, you can refuse to go. The next words you will likely hear, however, are, "You're fired". And that will be that.

The employer, not you, decides what hours you work. If you refuse to work the hours he wants you to work, which includes going home when he says go home, he is free to send you home permanently and hire someone who will work the hours the employer wants, without argument.