Here’s some of Rothbard’sa actual text from EoL:
Let us take a seemingly more difficult case. Suppose that a celebrated movie actor agrees to appear at a certain theater at a certain date. For whatever reason, he fails to appear. Should he be forced to appear at that or at some future date? Certainly not, for that would be compulsory slavery. Should he be forced, at least, to recompense the theater owners for the publicity and other expenses incurred by the theater owners in anticipation of his appearance? No again, for his agreement was a mere promise concerning his inalienable will, which he has the right to change at any time. Put another way, since the movie actor has not yet received any of the theater owners’ property, he has committed no theft against the owners (or against anyone else), and therefore he cannot be forced to pay damages. The fact that the theater owners may have made considerable plans and investments on the expectation that the actor would keep the agreement may be unfortunate for the owners, but that is their proper risk. The theater owners should not expect the actor to be forced to pay for their lack of foresight and poor entrepreneurship. The owners pay the penalty for placing too much confidence in the actor. It may be considered more moral to keep promises than to break them, but any coercive enforcement of such a moral code, since it goes beyond the prohibition of theft or assault, is itself an invasion of the property rights of the movie actor and therefore impermissible in the libertarian society.
Again, of course, if the actor received an advance payment from the theater owners, then his keeping the money while not fulfilling his part of the contract would be an implicit theft against the owners, and therefore the actor must be forced to return the money.
For utilitarians shocked at the consequences of this doctrine, it should be noted that many, if not all, of the problems could be easily surmounted in the libertarian society by the promisee’s requiring a performance bond of the promissor in the original agreement. In short, if the theater owners wished to avoid the risk of nonappearance, they could refuse to sign the agreement unless the actor agreed to put up a performance bond in case of nonappearance. In that case, the actor, in the course of agreeing to his future appearance, agrees also to transfer a certain sum of money to the theater owners in case he fails to appear. Since money, of course, is alienable, and since such a contract would meet our title-transfer criterion, this would be a perfectly valid and enforceable contract. For what the actor would be saying is: “If I do not appear at Theater X at such and such a date, I hereby transfer as of the date the following sum ___, to the theater owners.” Failure to meet the performance bond will then be an implicit heft of the property of the owners. If, then, the theater owners fail to require a performance bond as part of the agreement, then they must suffer the consequences.
http://mises.org/rothbard/ethics/nineteen.asp
So I guess it’s not as clear cut as I laid out, including the performance bond stuff. However under no circumstances can the employer compell someone to not work, or force them to work. Only to require a bond/payment.