Originally Posted by
gglave
I've chatted extensively with PTravel about this in a couple of different threads.
To be so bold as to summarize his position -
1) He will stay put in his assigned seat (ergo he will not leave the aircraft nor move seats.)
2) He will not sit next to an unaccompanied child.
After that, whatever else happens is not his responsibility. It is up the parents and the airline to work it out.
I don't think any airline is going to allow a small child to sit separately from his/her parent. If the child is young enough, the airline will do whatever it takes to make sure that at least one parent is sitting in the next seat. There is simply too much risk of things like sexual harassment of children, and they don't want the liability. Remember that the airline has the authority to assign you to a different seat for any reason.
So take your pick. Either move when the parent asks you, or wait for the FA to come and force you.