Maybe Yahoo didn't have time to sort through all those cases, but it shouldn't be surprised that:
1. Yahoo might have pushed out many people who didn't deserve it. Many of them are working parents and perhaps people with disabilities.
2. Yahoo might have pushed out "cheaters" without really telling them why, leaving them disgruntled about work-from-home policies instead of embarrassed that they were caught not doing their jobs.
3. Yahoo singled out a certain category of "cheaters" unfairly. I'll bet $5000 that there were at least twenty always-at-their-desks Yahoo employees who "wasted" a significant amount of time on HN, facebook, reddit, Yahoo video, or just talking about hobbies and sports with coworkers. Taking the ax to at-home slackers and ignoring the general slacker problem is slightly unfair. It doesn't project communication and transparency; it teaches employees to hide their routine from their bosses as much as possible.
If someone is working from home and not meeting their duties they should be fired. Eliminating the policy was a band-aid, having hard conversations and getting rid of the slackers (and their managers) would have been the cure.
[1] http://www.reuters.com/article/2013/02/26/us-workplace-flexi...
I ended up quitting because I was tired of watching my boss browse Facebook and sports blogs all day.
They still exist and will probably take another 18 months to wither and die. The experience taught me to look hard for red flags and to hold my company as accountable as myself.