Easier to stay under the radar if nobody is looking for you. Social Services can't get an order to take the baby if they don't know it exists.I'm sure that relevant authorities back up their intentions lawfully signed court orders?
Otherwise the law would mean nothing to anyone and no baby would ever be taken to a place of safety at birth.
The person I know of did not volunteer anything, their baby was delivered under supervision and removed very much against their wishes. Which was absolutely the right thing to do in that instance IMO.
But my point being is if CM and MG did not believe their baby was to be 'snatched' then they would have had no reason to flee in the middle of winter, they could have stayed put or even just relocated and not particularly notified anyone.
JMO MOO
If they slipped off the radar before anyone else knew she was pregnant, then they were far less likely to be tracked down by safeguarding agencies. They could settle quietly in some unfamiliar area and so long as they didn't draw attention there's a good chance the various databases wouldn't be joined up enough for anyone to catch on that they super shouldn't have a kid.
There are indications they had a few kids taken off them already. I think they knew it was a given at this point, and that the legal and safeguarding restrictions would start immediately after services found out she was pregnant. So the plan was to make sure that they didn't find out. JMO