In a downturn, I wouldn't necessarily assume that someone has sufficient gains to offset their losses. They could just be losing money.
Also, there are restrictions on how you carry forward losses and how much you can deduct in later years.
edit: I think the issue is you're being nuanced about the connotations of "accounting games" (I mention this downthread and argee that some tactics are straightforward.) the user [tiler] above, responded as if the recession explains how 35K people with $200K+ income had 0 tax liability, which is silly.
