The cynic in me sees this as a way that Google could e.g., pay someone 80% for an "official" 4 day work week knowing full well that the competitive types workin

The cynic in me sees this as a way that Google could e.g., pay someone 80% for an "official" 4 day work week knowing full well that the competitive types working for them will end up pushing themselves into a typical 5/40 work week (and beyond) anyway.