The dirty plates and cups start to pile up and hand in hand so do the excuses: " I am too busy", " It wasn't me", "I can't work the dishwasher"...
The more staff see other leaving dirty dishes, especially if their manager does it, the more they feel "justified" to do it too.
I know all of this sounds petty and not important but don't forget every employer has the primary duty of care to ensure the health and safety of workers and unkept premises can present hazards like slips, trips and falls, burns and food hygiene issues when using unclean utensils and crockery.
A good induction when employees start their job should include/cover basic office rules, health safety and legal obligations.
Don't write passive aggressive notes but a note aimed at responsible people with manners that were temporarily forgotten.
What else could you do?
Using own cutlery