>My understanding is that trading on non-public info isn't a crime unless both parties benefit.
Trading on non public information for a gain is going to land you in hot water with the SEC.
These two lines on the SEC site [1] define this.
>Corporate officers, directors, and employees who traded the corporation's securities after learning of significant, confidential corporate developments;
>Friends, business associates, family members, and other "tippees" of such officers, directors, and employees, who traded the securities after receiving such information