Everyone's thought about it! How many kids films have you seen where there's a 'big' fight and the brat runs away?
I've never done it though. When I was little, when I got soooo angry at my mum I'd write her a note and leave it by her bed. She saved a few and I can't even read them for the shame of it!
" I HATE YOU! You're [misspelt of course] the worst mum in the world! I hate you hate you hate you and I won't love you until you buy me that barbie,
NO LOVE,
Sakina"
... *sigh*.. the things you'd like to forget.
On the other hand my insane nephews who turns 9 next month has run away many times. Upset coz his parents got divorced. Little...so and so.

We didn't know what to do, so we just had to wait for him to come home.... to punish him, heh heh heh

Don't worry. we live in a gated neighbourhood and he was fine.