WHAT IS MACROING?
Macroing is the use of programs on the computer that automatically do certain functions, and the user does not have to be present. For example, a macro program could have a level 3 character cutting trees. When the user next logs on, that account may be several woodcutting levels higher. This gives macroers an unfair advantage.
JAGEX
Jagex, the company that created runescape, has done multiple things to prevent macroing. None of them are working. For example, jagex continually updates the random events, such as mysterious men, evil chickens, or smoking rocks. All these things will cause a problem for the macroer if not responded to. However, the problem remains that the macroing programs continually change to account for these. If a level 3 dies to an evil chicken, it's no big deal; the macroing program will just run back to the place. Should a level 3 be teleported to the mime's world, that is also not a problem. The character will probably logg off, and later, the real person will go on the macroer and complete the random event. Therefore, the account is not banned. Also, Jagex has made reporting macroers extremely difficult with the rule that you can not report more than one person within the same minute. At first, this may seem reasonable, but the few people who detest macroers are greatly deterred, since there can easily be 20 macroers on the same screen.
DON'T BELIEVE ME?
If you don't believe that macroing is a problem (and there are many who hold his belief), then take a look. I logged into a random world and walked to lumberidge and this is what I saw; I'm not sure how much quality these pictures will have, but I will tell you that there were 8 countable macroers in the first picture, only because I was unable to find a spot to right click that fit them all in. The second picture has 7; 4 in the background, 3 close up, and me in the center.