Most people tend to read a lot about IM disclosure, to clear it up you must read the big 6. To read these you can visit: http://secondlife.com/corporate/cs.php or read below.

4.Disclosure


Residents are entitled to a reasonable level of privacy with regard to their Second Life experience. Sharing personal information about a fellow Resident --including gender, religion, age, marital status, race, sexual preference, and real-world location beyond what is provided by the Resident in the First Life page of their Resident profile is a violation of that Resident's privacy. Remotely monitoring conversations, posting conversation logs, or sharing conversation logs without consent are all prohibited in Second Life and on the Second Life Forums.
You will notice sometimes to that people place information in there profiles somewhere stating that by im'ing them you are giving them permission to disclose information and or Im's with them. Some people tend not to see this and others do but don't agree with it. To prevent this you can do the following.

  1. In the beginning of every conversation with these people tell them that you don't give them permission to disclose any information you will provide them in this conversation.
  2. You can also add something to your profile. Provide the information above about disclosure and then underneath write something along the lines of  "I am just stating that I give NO permission of sharing any of my information or logs without written consent!"
  3. If you really want it to be known do both and place "2" somewhere it can clearly be seen in your profile.
After searching around I stumbled upon this: https://blogs.secondlife.com/message/28374#28374 this pretty much states that even if someone posts something in profile about im disclosure and not reading it you still consent will not hold up.

More information in detail can be found on wiki Second Life located here: http://wiki.secondlife.com/wiki/Linden_Lab_Official:Can_I_be_punished_for_revealing_information_about_another_resident_without_permission%3F it is worth checking out if you want more details or are really concerned about disclosure.