From what I understand, she doesn't seem to be held against her will. If Aaron Levin Smith is to be believed (being that he is a former Sea Org member, I'd say his credibility is good), she's been seen out and about running errands and the like, but always with a security detail. There's a decent chance that I'm misremembering something, though, so take this with a pinch of salt.
Aaron Levin Smith made a video on Shelleys whereabouts somewhat recently. IIRC she's in a compound in California somewhere and she's fine, by all outward appearances. I'm pretty sure she's drinking the kool ade like the rest of them.
Brace yourself. It's a train wreck.