Actually, some of you are reading the question incorrectly. This is an unmarried mom and dad of a common child who want to move together to Florida, and mom wants to make sure she can move back to NY with the child if things go awry down there between her and the dad.
So no consent is needed to move to Florida, and it's not really a tough question. Yet.
As some have said, different states have different laws, although the UCCJA has made things a lot more uniform.
Moving from NY to Florida is not at all an issue. Should things go wrong in Florida, causing mom to want to move back to NY with the child, several things come into play. First, you need to know what Florida's required period of residence is. Although it's been a while since I practiced in NY, I believe in NY & NJ it's the same - 6 months for some issues, one year for others.
If the child is in FL for 6 months or more, it is likely that FL will be considered the home state of the child, and mom will have to file an application in the courts there to move back to NY with the child if dad won't just consent. Less than 6 months, and mom may still be able to file the application in NY. Again, you need to check the FL period of residency for applications of this nature. Also, note that mom doesn't just get a free pass to come back to NY with the child if she's been in FL fewer than six months (or whatever the requisite time period), she just gets to use NY as the venue for the legal issues.
Other factors come into play too: How connected are the child and dad? How much input did dad put into the child's day-to-day life? Did he read the child stories at bedtime? Did he see the child every day? Get the child ready for school, etc? Again, this is all what's brought up at the hearing, mom doesn't just get free rein to pick up and leave with the child.
There's only one way that I know of offhand that allows mom to leave a jurisdiction with the child and run to another state before filing an application for custody, and that's when there's domestic violence. A DV victim escaping an abuser can, in some or most jurisdictions, pick up and leave with the child as long as, when she gets to the new state, she immediately thereafter files for an order of protection (in NY - in some jurisdictions it's restraining order) and for primary custody of the child. Again, you need to check with FL to see that they allow this.
FYI, should a hearing be necessary to determine whether mom can return to NY with the child, mom will need to show a few things. The bias, as opposed to past years, is to permit a custodial parent to move with the child as long as: (1) She can show that she should be the parent of primary residence and have primary custody. This isn't assumed, although most judges still favor mom in custody battles unless she's shown herself to be unfit in some way. (2) She shows an articulable reason for moving, that doesn't include "I want to keep my kid away from dad and mess with him." She should show that her family is in NY and can help out or that she's got a good job opportunity there, or that her life is really there and so is the child's and the stint in FL was just a short aberration in the family history. Something like that. (3) She shows the court a well thought out parenting plan for the non-custodial parent. She can't just say, "Well, I want to move and dad has to come to NY and make time to see the child." She's got to say, "Well, I thought about it, and here's a reasonable parenting plan I've come up with, so dad doesn't lose his ties with the child: He can have Spring break with the child, 2 weeks of each of the two summer months, every other Christmas. We'll make sure they're on the phone at least 1/2 an hour every evening. Or we'll get a webcam so son and dad can talk to each other every day 'face to face.'" That is the kind of parenting plan that will induce the court to allow the move.
Note that although the bias is now in favor of allowing the custodial parent's move, it still isn't easy.
