I agree with not getting caught in a lie. Personally I don't like the lie approach, even if I can't be caught because it forces me to remember two sides: the truth and what I've told people.

I think the take away here is that you shouldn't be discussing previous salary in any case. If I'm asked I always say "I'm not at liberty to discuss contract conditions at my previous employer" or something to that effect. As I mentioned: as a free market entity, I should be getting what I'm worth now, not some variation of what I was worth 2 years ago when I last tested the market.