@FrostbackCat  
Ponies aren’t colorful and can’t fly or use magic either if you think about it.

@WatermelonRat  
Exactly! It bugs me out of my mind that Twilight, the most knowledgable one, makes the most stupid mistakes of the bunch.  
(No hate, I still love Twilight and her adorable self, but still.)

@Evowizard25  
I’d say it was just for the audience’s benefit, but Spike noticed it.

@FrostbackCat  
Nappa: I get it.

Colorblind people aren’t exactly “shade blind” just Saiyan.

Yeah, I chalked that up to another one of Twilight’s stupid moments. (Poor girl has quite a few of them.)  
I mean, how did she not see that, or piece together that they weren’t themselves?

I’m pretty sure colorblind people can still tell a few differences like that.