Lets just say sir goby keeps an eye out for the blind pistol, while the shrimp is designing, excavating, and trimming up the burrow for them
. Any danger that is too great sends the goby whirling back to the burrow along with the shrimp.
I know the question was directed at Jason, but I thought Id help him out since I have the same thing in my tank, the only difference is that I have a blue spot watchman goby. The shrimp digs a ton of sand, daily and everywhere he is, goby is there scanning the tank for potential threats.
EDIT: Looks like he beat me to it.
@Jason: That YWG is very fat