“This example from the retail world should be instructive: if you have only enough employees to barely get the work done as is, you’ve engineered a scenario in which employees may have theoretical permission to take time off, but understand that they’ll shoulder the burden of that time off in some way. Either they try to keep doing part of their work while on leave, a colleague takes on an even larger work burden, or a portion of essential work goes undone, slowing everyone on a team.”