hi
years ago i went on a 3m course for this product and in those days they used to guarantee "No Stains" what the misconception was that people thought it meant that if they got a stain that could not be removed that they would get a new carpet. But what it really was a refund on just the product.
these product wear over time and need topping up regularly. people dont want to do that. so when they get a stain in a walk way they get very disappointed when it cant be removed.
Ian