If you rinse Starsan you are reducing it's efficacy by half.....
When we use a wet contact/no rinse sanitizer the way God and Charlie Talley intended (Not rinsing OR letting the sanitizer dry on the surface of the object) we are also creating a protective barrier on the object which prevents and subsequent micro organisms from rendering it unsanitized. It's like a double edge sword...it kills whatever's on there, but also kills anything that comes into contact with it after the initial kill, for as long as the surface is wet.
When you rinse off your starsan, you have elected to give up HALF of it's sanitization power, AND by rinsing it off with water, you also MAY be opening yourself up to infection from the very material you've used to rinse away the sanitizer.