Well her shackles, made of an indestructible alien alloy, are locking both her arms and her neck together, and the energy binding them all together can't be resisted by physical force alone. Plus she has a slave chip surgically implanted at the base of her skull, if she gets 90 meters out of range of the transmitter, the chip inside her head will explode. There also the fact that the bars of the cage is 6 inches thick, and made of reinforced tempered Adamantium. She will also be kept heavily drugged, chloroformed, tazed, and sedated, possibly gagged, blindfolded, stripped, and hog-tied later. You can never be too careful It will also depend on the kindness/generosity(or lack thereof), or incompetence of her potential buyer. Sabrina will be very hard-put to escape, unless another hero/heroine decides to save the day and come to her rescue, know anyone?
No doubt, bro! No doubt! She is definitely in quite a pickle here, I am not quite sure how she can get out of this one...she is gonna need some outside help, it seems. You up for a rescuing a damsel in distress?