Or you could simply have the managers confront the offending employees one on one instead of blanketing your whole staff with a policy change...
A company culture where the slack of certain employees gets discussed in a boardroom and the solution is to email everyone a policy change sounds suspiciously like a culture that abdicates the responsibility to lead.
A company culture where the slack of certain employees gets discussed in a boardroom and the solution is to email everyone a policy change sounds suspiciously like a culture that abdicates the responsibility to lead.