Re: Bad references
The problem with bad references that makes current employers loathe to provide them is that a bad reference will prevent the candidate from moving on of their own accord.
It isn't illegal to provide a true bad reference, just unwise given the tangled way some laws have of preventing a clean firing for cause.
Providing a bad reference can open one to charges of providing a false statement though, which can blossom into libel and damages lawsuits. Who needs that amount of bother when one can write "Lovely chap. Knows his stuff. Be sorry to lose him"?
On one of my contracts terminating I was given a bad reference when my agent asked for one. The reason given was so outrageously untrue I just laughed, even though it did cause me material harm in that I was out of work for a bit and the reference didn't help.
The real reason this paragon of truth had written me down? The whole department suspected I had slept with The Office Angel after a party, and I refused to gratify their prurient interest. She ended up going consultant herself within a month of my leaving so they lost their eye-candy, likely because she resented their attitude as much as I did.