Carrying this over from another board.  I'm curious just how pervasive this practice is.

The Scenario:

• You're out there and it's a beautiful day.  
  
• There are people on your desired campsite, but they're going to be leaving shortly.  
  
• Maybe you just want to start fishing right away instead of setting up camp.
  

I have taken my pack and put it on the campsite, visible from the water.  I have also been the party leaving and had a group leave a pack so that others know the site is taken once I vacate.

Is this a common practice?