I just do not pay attention to them. Unless someone seriously asks wanting info about the subject when I get asked where my buddy is I tell them that "today I don't have one" and walk away. I discuss solo diving with students as well because they will at some time see it. I don't want them getting the idea that they can just go and do it. I let them know what is involved with gear, training, experience, mindset, and especially what can go wrong and that the consequences are much more severe since there is no one to assist you. I am a firm believer in the buddy system if those using it know what they are doing and do it well. Problem is many have no idea just what a dive buddy is and with new divers that is the fault of the very instructors who use solo divers as bad examples. If everyone was really trained in diving with a buddy from the get go and worked at being a good buddy, there might not be as many of us who feel the need to dive alone as often rather than get saddled with a person who more of a liability than a true dive buddy.