A few simple rules

Most workplaces have rules ... but often these are 'conventions, unwritten but largely abided by.

This is OK until someone decides to break those conventions.

Unless the rules are codified, it becomes very difficult to enforce them. (Think about public establishments that have a dress code of 'smart casual' ... who defines smart ... or casual for that matter.)

So it is worth writing down the rules - what do employees do with their coats when they arrive, can they eat and/or drink at their workstation, what should happen at break times, when can those breaks be taken .. and so on.

It will make the organisation more productive if people know how they should behave under a range of circumstances. 

There is no need to be heavy-handed with this ... just issue a 'reminder' of the already-established rules - for everyone's safety, convenience and efficiency.