Oh AP Lux is legit. AD Lux...
Seriously, I don't know how I did that. Really. I had more kills than the ADC by the end. I wasn't even doing anything... I don't know.
Well if you're on an AP heavy team the enemy will naturally stack magic resistance. If your ADC was loosing lane they'll generally not bother with armour until it's too late. Going AD on an AP character can be a great way to duck out your enemy.