At present "not crossing Laxman Rekha" means to be within the limits prescribed by code of conduct or to act within the limits of one's authority. When a woman is asked to be within Laxman Rekha, then it often means that, being a woman, she should have little freedom.
Often people blame Laxman for putting limits on women's freedom. But it is gross misinterpretation of what Laxman did.
Laxman asked Sita not to cross the line because he wanted to protect Sita. He had no intention of curbing her freedom. Even now, when somebody's life is known to be in danger, he is often given police protection and he is asked not to go anywhere without the security. Can we say that there is any injustice in giving him police protection? Not at all. How can saving's somebody's life be injustice to him? If we know that somebody in our family will be in danger when he goes out, then we tell him to be within the house. There is no injustice here because we are merely trying to save his life.
Likewise, Laxman should not be faulted for asking Sita not to cross the line. If Laxman did not draw any such line and it was merely the imagination of the authors of some versions of Ramayan, who added this story, then we can blame the authors for writing something incorrect. But we must not blame the authors (nor the character Laxman in those versions) for curtailing the freedom of women.
Rather it is the fault of the people who interprete Laxman Rekha in wrong way and use it to justify treating women as some jail inmates.