Can a company bypass the lawyer and make an offer directly?

Still working my way through the series. In the episode “The Abstinence”, Kramer is disfigured by exposure to tobacco smoke. He goes to see the lawyer Jackie Chiles. They meet with a representative of a tobacco company who says they’ll have an offer by tomorrow. Although not shown on TV, the company contacts Kramer directly and offers him the chance to be on a billboard as compensation (with no payment no less).

So, first, is it so that if a person is represented by a lawyer, can the company contact the represented party directly?

I’m guessing no and since I suspect that will be answered instantly.

Suppose it did happen and Kramer accepted the offer, what would happen? Could Jackie then file a suit against the tobacco company? If so could he file it on his own behalf (since they’ve made an offer which cuts him out of the deal) or would he file on behalf of Kramer (since they shouldn’t have contacted him directly) or both?

Lastly, let’s suppose that the company had made the offer to Kramer through Jackie and Kramer still accepted. Could Jackie do anything about it?

Note: I’m looking for factual answers and although the genesis of the question comes from Seinfeld it isn’t really related to the show.

A lawyer is prohibited from contacting a person directly if they know that person is represented by counsel. A non-lawyer at the corporation could probably do it. Kramer’s lawyer has a case against Kramer (read your fee agreement), not the corporation.

IIRC, this is the third time that something like this happened. I wonder if Kramer could prevail, or at least mitigate his liability to Jackie, by arguing that he should have known what he was getting into?