No, she had to move because the bus driver couldn't keep his eyes off her. She can dress however she wants short of exposing herself. She's just a girl, she didn't have a neon sign abover her head, she wasn't screaming for attention, all she did was wear a low-cut shirt. And as Emon just said, if the situation was really so serious as to implicate the saftey of the other passengers, he should have told her in private.
And commenting on your first post in this thread;
I'm sensing some chauvinistic undertones here.

She shouldn't have to change how she wants to dress because some guy was staring at her. Taking what you said ("I shouldn't have to change, she should accept the consequences") reverse it and apply it to the situation, it becomes "She shouldn't have to change, the bus driver should accept the consequences" See? Bus driver should accept that he's a perv.
And being ***-naked would be breaking a law. This woman didn't break any laws by being smoking hot.
However, if I were on a bus in a mini and showing off my fabulous neck-line, I would expect the driver to respect my descision to dress the way I wanted to. I wouldn't expect it to be a problem.
Unless he was really gay for me.