Ds is 3.5yo and this Christmas he will really 'get it'. 
BUT I am almost certain he will ask father Christmas for an iPad. He is obsessed with his aunties one and would love it but
A) they are too expensive
B) he'd not understand about having limited screen time and would be on it 24/7 or have a melt down everytime we took it away.
So... What are the best, most believable reasons to give the dc when explaining why father Christmas can't being them whatever it is their hearts desire? 