As previously mentioned, there are two main types of hackers: those who are looking for any unprotected wireless network, and those who are auditing a specific network for ethical or unethical reasons.
In the case of the former, the goal will be driven by curiosity or malicious intent. Typically, this group will consist of script kiddies or hobbyists who are out to discover how many unprotected WLANs are in their area. The difference is in what happens when an unprotected network is found. A script kiddie will immediately try to discover what computers are available, and will install a back door or otherwise take advantage of the situation.
On the other hand, an auditor or professional hacker will have the goal already defined. In fact, the attack on the WLAN might only be one part of a whole security audit that includes Internet probing, war dialing (not to be confused with war driving), and social engineering attempts. In this case, the target is only to penetrate the security of the WLAN and determine whether it is vulnerable to an attack.
The difference between the two is night and day. A script kiddie will only be looking for a way in. Once discovered , he will use it to his advantage. However, an auditor will find the same weakness that a script kiddie will find, but she will also discover several other methods of attack, and will provide a relatively complete description of all the weaknesses in a WLAN.