Someone should mind their own business rather than staring at other customers on the plane and making silly complaints.
I don't usually agree with law suites of this sort, but:
She was a paying customer.
Her clothes weren't revealing anything unacceptable.
She didn't get on the plane expecting some kind of weird dress code.
The staff on the plane singled her out for no valid reason.
The company, whose airline she payed to fly on wouldn't even issue an apology for their poor behavior.
At the least she should get her money back and some to cover legal fees.
Yeah, I'm sure she'll sue for some ridiculous amount, that always seems to happen, but I think she is owed a little bit of something anyway.