Originally Posted by Bowgie

OP, put your toddler son in row 2 Take your assigned seat in row 1.
One of two things will happen:

1. You son can see you in the row ahead, be reassured, and behave well.
2. Son pitches a fit, and Mr. Rude will change his mind and swap seats.

If Mr Rude gives you any 'tude, you can tell him to STFU.
I forgot to add a title: "Call his bluff"