Well, if you're working 400 hours a week and only getting paid for 40, you've got serious problems.
If you're getting fixed compensation, make sure you know the expected hours before you accept the offer. If they ask you to work more than that, renegotiate or refuse. If you're getting paid by the hour, then you're being compensated so no worries. Don't be afraid of the labor market - it's good times right now.
