A. It's a “personality trait” shared by NO ONE else in the movie. No one. There was no coherent reason for her smoking whatsoever; it was outside the world of the futue, it was outside the world of a controlled-environment lab, it was outside the world of the movie itself(!)

B. It's an aspirational “personality trait” tobacco has tried to associate with female smoking since the 20s; it's propaganda, pure and simple.

Judging by all the booster seats outside the movie theatre entrances–and the number of kids in the house when I saw it–an entire generation is being sold on cigarettes in the same way cigarettes have been marketed to girls since the 20s, the message reinforced over and over, with each viewing, on all the TV reruns, for decades to come:

Strong, tough, independent, smart women smoke.

Realism? Ha. It's against all reality. This would be a seriously atypical scientist. 44% of cigarettes are sold to the mentally ill; most smokers are poor and uneducated. This is an ad, pure and simple. And millions of kids are getting the message.

You _should_ be annoyed, but not at me. I'm not hawking cigarette mantras to kids. This is no small deal.

Here's what the tobacco PR maven trying to hook kids in “Thank You for Smoking” said:

–Nick Naylor: Now, what we need is a smoking role model, a real winner. . . . two packs a day. . . .

–Jeff Megall: Sony has a futuristic sci-fi movie they're looking to make.

–Nick Naylor: Cigarettes in space? . . . But wouldn't they blow up in an all-oxygen environment?

–Jeff Megall: [long pause] Probably. But, you know, it's an easy fix. One line of dialogue: 'Thank God we created the, you know, whatever device.'

A second objection is that Cameron/Weaver go 150 years into the future to spout 80-year-old tobacco propaganda.

In the 1920s, American Tobacco Co. hired Freud's nephew Edward Bernays to get women smoking. His solution: promote smoking as freedom and independence. Bernays hired debutantes to walk down 5th Ave during the 1929 Easter Parade dressed as the Statue of Liberty, holding their cigarettes aloft as “torches of freedom.”

Bernays later deeply regretted his work for tobacco companies.

Independence/rebellion is an ad theme Cameron falls for and promotes with Rose's character in “Titanic,” too.

Weaver's stress-relief is another tobacco advertising mantra, used since the 30s at least, with lots of jet pilots, sports stars, etc., “calming their nerves” with cigarettes.

Cameron's unconscious swallowing of tobacco propaganda shows he really doesn't understand the issue; his rationale is specious. He is fooling only himself.