I'm not going to defend texting in the theatre, but perhaps if the show had been more interesting, she wouldn't have focused on anything other than what was happening on stage. I don't blame her for losing interest in it, for it got boring real fast.
Still, it would have been better for both her and the audience if she had just walked out.
Unquestionably, a cup of tea at a nearby café would have been far more more agreeable than Hamilton, and she could have texted to whomever she wanted without either lectures or reprimands from Mr. Miranda.