Here's a short primer from the American Bar Association on the legal aspects of quarantine/isolation orders. IMHO, the scientific basis of a quarantine can be argued either way, although the experience in Madrid and Dallas seem to support the argument that Ebola does not spread easily in First World conditions before symptoms appear.

No secondary contacts of any of the nurses in Madrid or Dallas came down with Ebola, and even the people in the same apartment with Thomas Eric Duncan when he was quite ill did not contract Ebola either. Dr Nancy Snyderman and members of her camera crew did not infect anyone and almost certainly Dr Spencer did not either (although it's still early in his case). But forcibly putting people in a tent with a port-a-potty and no shower makes no sense to me. There is no reason why people who are not symptomatic could not be quarantined safely at home.

While I think an argument could be made for the medical necessity of some sort of quarantine, from Hickox's description of her experience, sounds like her due process rights outlined in the ABA article were not respected, at least not for a while.

Gov Cuomo has modified NY's quarantine procedures, and although Gov Christie has not, he has already backtracked by allowing Hickox to leave quarantine and return to Maine.