But Rowsley would not have turned her back to travel alone: that is, without a man to guard.

He 's too chivalrous.
The sending of Weyburn, she now fancied, was her own doing, and Lady Charlotte attributed it to her interpretation of her brother's heart of chivalry; though it would have been the wiser course, tending straight and swift to the natural end, if the two women and their Morsfield had received the dismissal to travel as they came.
One sees it after the event.

Yes, only Rowsley would not have dismissed her without surety that she would be protected.

So it was the right thing prompted on the impulse of the moment.

And young Weyburn would meet some difficulty in protecting his 'Lady Ormont,' if she had no inclination for it.
Analyzing her impulse of the moment, Lady Charlotte credited herself, not unjustly, with a certain considerateness for the woman, notwithstanding the woman's violent intrusion between brother and sister.