Burr Incorporated spends approximately 20% of its budget on employee benefits. In an effort to curb costs, Human Resources has decided to run a pilot program with volunteer employees, in which volunteers received a 5% raise in pay for a 25% reduction in benefits. During the first year of the pilot program, the volunteers` productivity matched or exceeded their previous performance. Burr Inc. has concluded that implementing the pilot program company-wide will not only save Burr money, but also increase productivity.Which of the following, if true, would provide the strongest justification for Burr Inc. not to implement the pilot program company-wide?
【选项】Promotions amongst those in the volunteer group were contingent upon their performance while in this group.