Not sure what danger they could collectively compose. We never knew Flurry as an adult, but judging by the stained glass in The Last Problem, she was much like her mother and Twilight. For Luster, all we know is she started out much like Twilight. Yes, Cozy was a little shit. But with this image they all appear as adults. Unless they all decided to go evil, I don't see a problem here.
Even then, with the way they are looking at the camera I'd be willing to accept the situation. You could even say I would be enthusiastic about it.
Not sure what danger they could collectively compose. We never knew Flurry as an adult, but judging
