Silence is golden

I read a post this morning by a fellow blogger about sibling rivalry so thought I would have a rant as well.
Son no 3 is born on an odd dated day and Son no 4 is born on an even dated day.  So a few years ago we implemented a rule which has worked well so far.  The rule is as follows:
On an odd dated day – Son no 3 gets to sit in the front seat of the car.  However, it is also his day to do the chores. On an even dated day, the rule applies to Son no 4.
Easy to understand and this has worked for many years.
Except this morning!
We all get ready for school and I go out to my car to do the morning school run – only to find Son no 3 is sitting in the front seat.  Son no 4 is standing next to the car demanding he gets out.  Son no 4 sees me coming and of course comes hurtling towards me, insisting I tell Son no 3 that it is not his day and he must get out NOW!
So I get in the car.  I politely tell Son no 3 to please move into the back seat.  He refuses!  So I close my eyes and sigh!  Just what I need first thing in the morning.  I explain to him that there is a rule – and he knows the rule – it has been in force for many years.
So he snarls at me – “it is a stupid rule – it wasn’t in place for Son no 1 and 2 – so why must we put up with stupid new rules”.  
And he still refuses to move.
So I had to get angry and demand he moves or else!
He finally moved.  And I drove them to school in absolute silence – perhaps there is a God after all!