According to The Jedi Path, in the section on Jedi Recruitment, many Jedi feel that a child being Force strong is devine permission to take the child. The arguement given in that book against those who claim the Jedi are kidnappers is that the Jedi have the legal right to take the children and thus are not kidnapping anyone. Bascially it is OK because the Republic says it is OK. The Essential Guide to the Force, written IU by Tionne Solusar of Luke's order, claims that Old Jedi Order would seek consent. The Jedi Mind Trick itself is not as easy to beat as Obi-Wan would have us believe in ANH. As evidenced with the Jedi mind raping Bane in Season 2, its pretty hard to stop the Jedi from getting what they want if they are determined. I can not personally recall evidence of a Jedi taking a child from a parent by use of brute force. I'm guessing that its pretty unlikely.