Open Windows And Closed Minds.
As she looked back on the day's events, Muffins felt that while the day started out rockily enough given her blunder with the date on the invitations and the resultant scrambling to fix things, the wedding ceremony itself made it all worth it in the end. All that was needed as to have the wedding guests file out so that Amethyst Star could get her team to turn a wedding chapel into a banquet hall and a fine time would be had by all. It felt sort of odd seeing her taking charge again after she'd been kind of shunted aside as "the town organizer" by Twilight Sparkle. Ah, well. no matter who had arranged the seating, they'd still have had six chairs left empty.
It was just then that Muffins asked herself a question that had an almost immediate answer: without realizing it, she'd locked what everypony were starting to call "The Guardians Of Harmony" out of the ceremony by accident. Oh, dear. Not only was that another mess to clean up somehow, Fluttershy was the only one of them who wouldn't make a point of being an irritant about it. Sure, Princess Twilight might have made a nice little speech about the town through the window the flamboyant best lake serpent left open but it was sort of understood that somepony with a big mouth, a lack of patience and the unswerving belief that Muffins had been put on the Earth to aggravate her awesome self would make a huge stink. Worse still, the few times that Sparkleflanks had come to her 'defense', Muffins was left with the distinct impression that somepony who's just as big a screw-up as she was thought of her as either a filly who'd never grow up or a sort of talking animal. This left her with the lovely non-choice of waiting for the inevitable passive-aggressive sniping about a foul-up that like about half the townsponies could have made.
Once the guests started filing out, the same six ponies who'd been having a warm and fuzzy moment had, as she'd guessed, turned into an angry mob bent on castigating her about what an inconsiderate, clumsy fool she was for accidentally locking them out of the wedding ceremony.After about a minute or so of this, she produced a whistle from somewhere, gave it a mighty blast and said "Uhhhh......pardon me. You'll notice that you're yelling at me right next to the window the sea serpent guy left open. I overheard the princess here do her little 'I love this town speech' through this open window. Why didn't it occur to any of you to, I don't know, climb through the open window instead of yelling at me afterward? And why have you all stopped talki.....oh. Hello, your highness. I'm sorry for yelling at your student."
As Princess Celestia smiled and said "That's quite all right, my little pony. I too would like to know why they didn't simply climb in through the open window. It isn't as if anypony would have noticed aside from Mayor Mare; everypony was looking at the ceremony, not at the front side or the side windows," Muffins looked around at Twilight Sparkle and her friends and debated whether it would be appropriate to stick around and listen to their answers.
After all, it wasn't as if Miss Rarity's answer wasn't going to be "Proper ponies don't climb through open windows even if they've been barred from some place by mistake. It's best to sit around and pout instead of looking like the daughter of a failed hoofball player living in the past as he asks us if we all wannabuyalottahorseshoes and a stretch-pants wearing irritant who eats bon-bons." This impressed Muffins as being a snobbier way of saying what Fluttershy would have said: "It, um, isn't NICE to fly through open windows or knock on doors when ponies goof up."
She knew Rainbow Dash well enough to know that sticking up for Fluttershy meant that her natural inclination to holler "LET US IN, FEATHERBRAIN" in a voice so loud, the dead could hear it had been set aside so her wispy little friend wouldn't collapse in a heap but what that didn't explain is why Princess Twilight managed to talk Applejack and Pinkie Pie out of simply climbing through the open window. Since it just dawned on her as if Princess Celestia wouldn't have cared about that breach of protocol, it baffled her as to why Princess Twilight would honor something that clearly meant nothing to her idol. Honestly, it was like how Rainbow Dash went overboard trying to impress the Wonderbolts despite their kind of not seeing the point of...oh. She'd just then realized that Twilight thinks Celestia expects more of her than she actually does.
That explained a lot. She didn't know why it had never occurred to her that this was the case but, as Muffins listened to one princess explain to an underwhelmed other princess that she was simply doing what she only did what she thought was expected of her because princesses have to set a standard of behaviour, she'd consoled herself with the fact that she and the former librarian hadn't exchanged more than two or three words since she moved into town all those moons ago because of the whole "I don't need to hire a courier service! I'll just rely on this overgrown salamander I'm bossing around to send MY messages for me!" thing so it's not like they were friends or anything. Aside from Pinkie Pie and Rainbow Dash (who mostly talked to her like her brains were in a box some place), she didn't usually interact with the other five either. Locking them out was a bad thing to do and she felt bad about it but it was a sort of abstract regret; inconveniencing those she knew better felt worse.