Just because a dog does not appear to be matted, does not mean they are not matted. Matts often feel like extremely thick spots of hair. As you can see from the picture below, this dog does not appear to be matted, but he is underneath. This can be seen in the other pictures. Matts are not always visible, or easy to spot, & sometimes, the top layer of hair is brushed out, while matts have developed up close to the skin, this is why the comb is an essential part of the brushing process, because a comb keeps the hair separated all the way down to the skin. Also, matts cannot generally just be cut out, because, as seen in the pictures below, most of the time matts are all interconnected to one another.
Anyone can shave a pet... It takes a professional to Groom your pet.