Make sure your aunts/parents know.

Sure, you can stay with me Scootaloo if that’s what you want.

No, you don’t, kid.
 
In this world of mine, everybody wears a mask, of sorts, to hide what we truly are. No one is ever what they appear to be. Even I hide my base self through a series of masks, running so deep I don’t even know what my true self looks like.
 
You, however, are different. Young. Innocent. You do not wear a mask. You have no need to. You have not been corrupted by the vices and temptations of this world. It is… beautiful.
 
I have done my best to preserve it. Though you may think my rules have been strict, it has only ever been to keep your innocence intact. But I cannot protect you from this world forever. You do not belong here, Scoots. You belong back in Equestria, with your friends and family. Not in this world of vice and temptations. There is a place where we each belong. This is not your.
 
Go.Back to your home. And know that I will always remember you.

Scootaloo
 
You must go back because things are not going well here on earth

“we’re already in equestria, silly…”

Inside of us, we both know that you belong in Equestria. If that portal closes and you’re not on the other side of it, you’ll regret it. Maybe not today, maybe not tomorrow, but soon, and for the rest of your life.
 
Here’s lookin’ at you, kid.

Well that’s too bad! You don’t belong here! In fact,you’ll never be happy here! I don’t even like you NOW GIT!  
watches her run away crying  
I-I’m so sorry, but I had to kid… I’d rather you hate me for doing the right thing for you then love me for beign selfish. Good bye…

You must go, your ponies need you!  
beat  
Okay, sorry. But seriously, this isn’t the best place for you. Your friends miss you no doubt, Dash is going to worry, and I bet you anything you like that the entirety of Ponyville will be turning the town upside down looking for you.
 
Earth is populated by humans who would have a panic attack if they saw a Pegasus, let alone a Pegasus that could talk. There’s way too much that can go wrong, and I can’t hope to save you from even a fraction of it. A life here isn’t a life a filly like you deserves.

“I think you’ll find that Equestria pretty much covers everything.” -TS

TOUGH.
 
shoves

You can always stay here with me

But that’s where your friends are, sweetie…I mean, kid. You can’t just give them up, can you? Apple Bloom and Sweetie Belle. Rainbow Dash. Come on, you know staying here isn’t worth never seeing her again, right? This is hard for me too, but it’s for the best. It’s where you belong. Now….(stifled sob) you better go before the portal closes.  
(through tears)Go on! Can’t you see we don’t want you here?! Go!!
 
….goodbye, my friend.

tl;dr version = Traitor!

I can’t say no to Scootaloo.

But Mommy, i don’t want to go to school today! I want to stay home and bake cookies with you!