I can see both sides on this. I don't know if the TDC was doing BDO functions, but someone who loved children would probably do the "interview" in a less intimidating manner - I mean, the 3 year old did cry and seemed scared, so obviously something went wrong. Did the TDC do the "interview" with BDO intentions, or was he just trying to be friendly and doing it in the wrong way?
Either way, the situation was handled in the wrong way, and the parents, IMHO, should have been more assertive and told the TDC (in a nice but firm way) to back off. I don't know if it's SOP to interview kids, especially infants, if they are deemed "suspicious", because of the legality issues involved, but the TDC obviously did it in a way that rubbed the family the wrong way. If this is a larger indication of what's to come (more interviews, more intimidation, children being asked questions, etc) then that's not a good sign. I really don't know. There's many possibilities here.