Thankfully booking agents are a dime a dozen. At times it seems as though everyone whom has made a trip to Africa is looking for a means to return on the cheap, few do it as a sole means of income.
I doubt Mark's return on this particular trip was more than a couple hundred dollars from each client to begin with as he originally set the first trip back in 2007 as a 24HrCampfire group safari at a reduced rate.
That doesn't erase nor excuse not following the best interest of your clients. Had he doubted the operator he should've made the changes in his planning of the group hunt back then. Surely not reused that operator until all bumps were ironed out an defenitely allow clients to make changes in operators even at his cost to cover their butts. Refunding all deposits of clients opting out because of the switch.