Why didn't the Little Seamstress warn them about leaving?

The Seamstress’s choice to leave without warning, is in many ways inspired by the boys themselves. For much of the book, Dai seems to implicitly approve of Luo's patronizing attempts to 'educate' the girl. Though he certainly feels real affection for her, Luo sets out to mold her into the likeness of the women he knew and misses. However, his efforts backfire when she moves to the city – without him. It is as though Luo wanted her simple enough to be dependent on him, but sophisticated enough for him to enjoy. Dai makes no explicit comment on the distinction between city and rural life, but does suggest that the two can never fully co-exist. We cannot have everything at once.

The final line is profound and nuanced. One could understand the sentiment as superficial: she wishes to exploit her beauty in the city. However, the significance is far greater. The Little Seamstress, as a rural victim of Mao's policies, had little opportunity to develop a self-worth and individual identity. Instead, the villagers are forced to work under a communal model, unable to question the dictums enforced from above. These dictums manifest into situations like her lack of options when she becomes pregnant. These strict expectations are horrific to consider, and help us understand the challenges of repression.

However, both through the boys and through Balzac, the Little Seamstress comes to develop a self-worth. Her admiration of her beauty is not vanity; it is a statement of pride in who and what she is. Rather than being defined the way that the village wants her to, she will define herself. She will not waste her "treasure" on people who refuse to properly appreciate it, but will attempt to declare her own identity to the city world, which might allow some semblance of individual liberty and expression. She is refusing to submit