In the Interactive Brokers list of fees for Corporate Actions & Dividend Processing, there is a "$100 + external costs" fee for "requests to exercise Dissenter or Appraisal Rights". Under what conditions would I want to request to exercise Dissenter or Appraisal rights? If I disagreed with what a publicly traded corporation is planning to do, can't I simply sell my shares on the stock market, instead of paying $100+ to exercise my dissenter and appraisal rights?