It should come as no surprise that shaking extra salt on food is a BAD idea.
First, nearly all of us (Who doesn't?) consume some processed or pre-packaged foods and nearly all of these have some, or a ton, of sodium. Everything from bread and cereals, to chips and crackers, to canned goods to frozen meals contain anywhere from 5% to 45% of an individual's recommended sodium intake--PER SERVING. (My beloved Peanut Butter Puffins deliver 230 mg, or 10% of the RDA in a 3/4 cup serving, which is about 1/5 of what I'll typically savor each night.)