Pinkamena Demon Pie,
A round of congratulations are in order. First, extend it to Mr. and Mrs. Cake for producing two children. Extend it again toward Mrs. Cake for her incredible tolerance for every "bun in the oven" joke she's no doubt heard throughout her pregnancy. You and I both know she's heard that too often.
Second, congratulations on learning the same lesson Fluttershy learned a while ago, only with more mature wording. This is shocking given your predisposed tendency to make everyone around you slightly nuttier within a twenty yard radius, and that includes babies. Given how much you know, I'm more shocked there was anything for you to even learn at all, because you have more people skills than anypony in town.
Third, congratulations on Pinkism finally taking some roots here in Canterlot. One of your devout believers came by with pink pamphlets detailing the wonders and enjoyments of living under an almighty watchful eye that, curiously, was yours. I'm looking at it right now, and it's really creepy. Do you know that? This thing will spook ponies, and probably a cockatrice.
I-I think it just moved. It followed me for a second. That's... this is going in the trash. Thanks, but no thanks. Pinkie Promises are as far as I'll go with you, but this is too much.
Anyway, I think I'll just close this letter before--
O-Oh! Hi Pinkie! You... you're in my trash bin. That's new. Super creepy, but new.
No, I didn't scare your follower. What are you talking about?
Oh please, it could have been any larger-than-average white horse with a flowing colorful mane. There's maybe three or four others with that physical description I've seen today on my way to Cuppa's!
Okay, I'll give you that Alicorn is really specific, but we have plenty of actors here in Canterlot, and they have replica horns and wings! It could be one of them!
I expect you to believe what you will. But I Pinkie Promise that I did not spook your follower out of town.
Good, glad that's settled. Wait WAIT, you forgot--
Oh well, you'll get this letter anyway.
Sincerely,
Princess Celestia
Oh, there you are Lu--you spilled the flour again, didn't you? Don't lie. You're covered head to hoof in... the... stuff...
Sister, you didn't happen to spook anypony in town today, did you? Perhaps a pony waving around... pamphlets?
Luna, lock your doors tonight. LOCK. THEM. ALL.