I am at a certain level in a big company with a salary range that is quite large. Many people at my level earn £5000 - £7000 more than me, mainly because they have been around in the company a lot longer.
In my last interview, I was offered a job and the company offered me my current salary + about £5000 (I was honest about what I was earning when they asked). Now, being that many of my collegues were currently earning that for doing the same job as me, I always wondered if they would still have offered me a £5000 bump if I had exaggerated my salary by £5k to start with.
I guess I will never know, and I didn't take that job for other reasons, but the guy really wanted me to work there, and I got the impression that he was trying to tempt me in with an offer that is just big enough compared to my current salary, without really reflecting on my skills and what they were worth.
I decided then that my salary would be exaggerated a little to any agencys or interviewers who ask so I can try and negotiate a better deal, ethical or not.