I cant see many portable operators, who put a detergent through their machine (self neutralising or not) then once finished - refilling with water and rinsing the 'Whole carpet ' just purely on the impracticality of it, (moving furniture back & forwards etc). Another point, arent those that pre-spray the detergent onto the carpet then acidic rinse off, still leaving some residue behind - most acidic rinsing solutions still contain some detergents.
Not that I am disagreeing with the idea of pure rinsing, and obviously would be easier for a TM operator. However, pratical wise?
Dave.