I didn't know that. That's cold man.
Think about it... let's say the slate for block production is as follows:
D1, D2, D3, D4, D5. Let's say D1 is a good honest guy and D2-D5 are playing dirty.
D1 produces a block, but as soon as he does, D2 builds a longer chain based on last block before D1 and marks it as missed. Then D3 confirms it, and so does D4 and D5. Now they have the longest chain of decent looking blocks. While good guy D1 has bad rep.