I think at this point there's a tension between the strategic advantage of having billionaires willing to surrender (preserves forces, results in net gain of manpower) versus how fucking stoked the majority of people are to see them die (gains new loyalists, results in net gain of manpower) and to be honest I think that someone sitting down with a pen and paper could work out an optimal percentage that could then be applied on a case by case basis. No-names with vast fortunes? Whatever, reeducation. Your Bezos', Princes, Duponts and Langones? Written off by popular demand.

Edit: having thought about this more, I think you could even get the best of both worlds by rocking up to one of these fuhrerbunkers and announcing "We will be accepting the surrender of the employees but not the boss. In fact, any employees who feel like doing a little mutiny and bringing the boss out to us, or even just forgetting to lock the gate, will be handsomely rewarded."