I'm not so concerned about silver in the wash water. After all, most of us have silver dental fillings. Additionally, people seem to eat off silver tableware with no ill effects. And practially nobody drinks laundry wash water... 
Like others here, what I'm more concerned about is that the "silver sanitation" feature will lull people into thinking that inadequate temperatures, detergent amounts, and wash time that result in still-soiled laundered fabrics will be ok since the silver will kill everything anyway. This is one reason why I'm so much of an advocate for laundry phosphates and hot water - they seem to clean better than anything else out there, and if the fabric is clean then the germ count will naturally be low.

Like others here, what I'm more concerned about is that the "silver sanitation" feature will lull people into thinking that inadequate temperatures, detergent amounts, and wash time that result in still-soiled laundered fabrics will be ok since the silver will kill everything anyway. This is one reason why I'm so much of an advocate for laundry phosphates and hot water - they seem to clean better than anything else out there, and if the fabric is clean then the germ count will naturally be low.