OK, but really, this does not boil down to a question of morality. The legal position is clear.

If the company paid for the ticket, then the company has the beneficial interest in the ticket. For a person to convert those tickets to his own use without the consent of the beneficial owner is theft.

No amount of rationaliztion, moral debate, or misconduct on the other party's part can render an illegal act legal.

That being said, it is perfectly open to negotiate. Buy it off the company for, say $0.10 on the dollar for the face value of the ticket. You get a dirt cheap ticket, they get a little recovery they would otherwise have lost.