I went to the Apple Store because the clicker on my Jailbroken 3g's headphones quit working. This is actually the third time the clicker has stopped working (Either I am pressing it too hard or maybe because I wear it a lot when working out and maybe the sweat is killing it).
I spoke with a representative about the problem and he said that he would get it swapped out for me. Every time before they saw I had a 3g and it was obviously still under warranty so they swapped it out no problem. This time after the rep went to get a new pair of headphones from the back, and he asked to see my phone. I turned off all the changes in winterboard before entering store and thought they wouldn't check because they hadn't in the past. Anyway, I showed the rep the phone and he asked if it was hacked. I promptly said no. He said he needed verification so he hooked it up to his macbook. By this point I knew I was screwed and would have to come back later. He of course said the phone was hacked and that was why my headphones didn't work. I told him that I understood the policy but don't bullsh!t me that jailbreaking my phone would mess up my clicker. After a few minutes of pleading he went ahead and swapped it out for me.

He told me next time to restore my phone before bringing it in so that they couldn't tell it was jailbroken and I wouldn't have any problems with warranty issues.
I knew better but didn't want to go through all the time of a restore. Guess I lucked out.
Anyway sorry for the long post but I thought someone might find it interesting.