Kinda wish I’d looked this up sooner and/or had participated in the discussion no doubt happening on the forums, regarding Season 6 as it’s happening. Although there’s not a post with the scene I’m about to bring up…
 
But did anyone else remember during this scene, that what Rarity said is NOT true? “Ooh, I’m sure I still have the dragon costume we used last time we snuck into the Dragonlands!” …Either the writers screwed up like I think they did in another past season reference for this season so far (well, maybe: when Pinkie Pie and Applejack were in Ponyville for Hearth’s Warming Eve this season, compared to in last season when they spent it with Pinkie’s family; if not cause it was Starlight’s first one with them or something), or that was intentional despite Rarity’s usual attention to detail (in terms of fashion, not necessarily at organizing things too, like Twilight)… as Rarity and her friends ditched the costume when they decided to defend Spike from the other dragons, and hadn’t brought it back with them! I hadn’t on the first airing, but watching it again online made me realize that!
 
Of course, they’ve done other continuity errors in the show: last season having Hearth’s Warming Eve and THEN Nightmare Night episodes back-to-back (at least, in the initial airing); season 4 showing Rainbow Dash to have amazing depth perception and noting things as she flies, despite in season 1, she missed seeing a mountain when she was trying to get away from Pinkie Pie (but that could be cause she was looking backwards then, not like she was in that later episode); Pipsqueak’s brown-spotted eye being different on his at least three (major) appearances to date. Those are just the ones I’ve noticed/recall at this moment.
 
As far as the mud goes, I hadn’t thought about it but it’s probably common sense: she expressed more concern over her friend’s well-being than for her own “fabulousness”. Even if she did say in the beginning that she was using him as her basket-holder, rather than as her bodyguard; since she does use him for things sometimes and I imagine she added that to not make him feel bad, perhaps. But yeah, this is kinda cute, even if Rarity’s covered in dirt or possible bat guano! x.x

That’s not mud. (readies a garden hose, holding one’s nose)

@Brony_Conundrum  
She has come a long way.

Hugh Herbert?
 
Someone will get that.

Pony clap

Whaddaya know? She really does love being covered in mud.