(FORTUNE Magazine) – For years, one of the worst kept secrets in business was the extraordinary lengths that CEOs had to go to in order to be terminated "for cause," and thus forfeit their stunning severance payouts. Screwing up royally wasn't enough. Sometimes neither was being charged with a felony.

Now it appears that at least one oft-maligned corporate board has found the backbone to expand, rather than limit, the definition of for-cause termination. In an October filing, Disney disclosed that in new CEO Bob Iger's contract, "cause" can include his "failure to cooperate ... with any investigation or inquiry into his or the Company's business practices ... including ... Executive's refusal to be deposed or to provide testimony at any trial or inquiry." What that means in English is that if Iger stonewalls an investigation (like, say, former AIG CEO Hank Greenberg) or pleads the Fifth, the board can send him packing without his golden parachute. "This clause is quite unusual," says Stephen Fackler, an attorney at Gibson Dunn & Crutcher who's crafted hundreds of compensation plans. "Presumably it signals the efforts of the board to establish a different sort of board-CEO relationship in the post-Eisner era." Disney declined to comment.

Don't expect other boards to mimic Disney's move overnight. Change is glacial in executive comp, and what's more, if the clause was ever enforced, Iger could theoretically argue that he was wrongfully terminated for exercising his constitutional rights. But the more oversight by the board, the less chance it'll ever come to that.