Maybe it's not blackmail, per se, but it's quite despicable.  What is done is the kids are used as tools to get money from parents, the government, and who knows who else!   Anyway, what should be done?

This is a touchy issue cause of the grandparent's, for instance, love of the kids.  However, though, 0 crap should be taken from psychos.  In that case, the offenders need to be driven out and creative ways need to be made to access the kids - without the Bonnie and Clyde parents!