3's first thought was that sounds like something related to clams, but she peers over Rarity's shoulder to see an example. That hat looks like a very tight fit. "I'm not sure... that looks like it'd be too tight for my tentacles to fit under. Or it'd look super weird and not very fresh."

And that would be the true crime. It wouldn't be a problem if she could wear the hat normally with her tentacles hanging down, but she can't.