Usually this means things like 'if the boss is ten minutes late to every meeting, staff will assume it's acceptable for everyone to be ten minutes late to a meeting'.
Given Zuckerbeg's reputation for sneaky behaviour and this example of his PR team, I now have an excellent example to share in the future: 'If the boss uses sneaky, underhanded and/or arrogant methods to launch 'his' business, staff will assume it's acceptable for them to use sneaky underhanded and/or arrogant methods to promote it'.