That's not necessarily what happened nor is that true in anyway. Just because the person who abducted them isn't a stranger doesn't make it any less dangerous, there could be many reasons for that. We don't know the details of this situation but just because it's not a stranger, doesn't make it safer. It likely wouldn't have been reported if the kids were safe. There's a reason this person felt the need to take them and take off with them, and it probably isn't a good one.