What is your policy on whispering at the office? I have found more often than not an office where whispering goes on is often one full of distrust.
In cubicle world, retail, hospitality, or other businesses where the difference between privacy and the public eye is minimal, whispering is often required to avoid interrupting others. However, if communication really was up to the level that it needs to be, whispering wouldn't go on as people wouldn't be afraid of what everyone else was saying.
Next time you think about whispering, consider talking louder so everyone can hear, or take the conversation behind closed doors