A half-free will?

by JLS
for the GC

Not for the Romans. From wiki:

"Libertas was associated with the pileus, commonly worn by the freed slave (emphasis added):[6]"

"Among the Romans the cap of felt was the emblem of liberty. When a slave obtained his freedom he had his head shaved, and wore instead of his hair an undyed pileus

πίλεον λευκόν,

Diodorus Siculus Exc. Leg. 22 p625, ed. Wess.; Plaut. Amphit. I.1.306; Persius, V.82 --.

Hence the phrase servos ad pileum vocare is a summons to liberty, by which slaves were frequently called upon to take up arms with a promise of liberty (Liv. XXIV.32). The figure of Liberty on some of the coins of Antoninus Pius, struck A.D. 145, holds this cap in the right hand.[7]

Libertas was also recognized in ancient Rome by the rod (vindicta or festuca),[6] used ceremonially in the act of Manumissio vindicta, Latin for "Freedom by the Rod" (emphasis added):

The master brought his slave before the magistratus, and stated the grounds (causa) of the intended manumission. The lictor of the magistratus laid a rod (festuca) on the head of the slave, accompanied with certain formal words, in which he declared that he was a free man ex Jure Quiritium, that is, "vindicavit in libertatem." The master in the meantime held the slave, and after he had pronounced the words "hunc hominem liberum volo," he turned him round (momento turbinis exit Marcus Dama, Persius, Sat. V.78) and let him go (emisit e manu, or misit manu, Plaut. Capt. II.3.48), whence the general name of the act of manumission. The magistratus then declared him to be free [...][8]

And so on.