imposing uncertainty on task estimates is a natural way to push back on management pressure to low-ball estimates
if everything has a potential 2x blowup, you monte carlo all the tasks to produce a distribution of finish dates, not a single 100% delivery date
institutions naturally push risk away from political power, so mostly this uncertainty is applied to line workers by managers. but senior managers have an incentive to push uncertainty to middle managers, not to line workers. uncertainty is a management trick to do this.