I would like to encourage all of us to groom brush out our carpets before taking photos! The classic "vee" pattern is not so classic it's just habit borne of making sure that the customer knows we stroked the carpet and didn't miss any areas. I've used a Rotary extractor for 28 years and had some customers that actually liked the swirly marks left by the 360 head.
With photos though we need to get rid of the shading marks left by wand or rotary strokes. It messes up the whole visual effect. When present in the room our brains process the image differently and the impact is quite different. A photo just copies all the shading strokes up and back as dark and light and look dirty and clean.
My new photo technique is to clean right through the middle of a really bad section then when perfectly extracted I groom the just cleaned area with a brush (grandi-Groomer). Now that's a powerful KODAK moment! I'll dig up some photos and post. The difference is great for website and promotional media.