A lot of my coworkers work from home on Fridays too. Which means a three-day weekend / nothing to show for their time on Monday.
Do you really know what your teammates are accomplishing? Or how they are spending their workday? Do you go to their homes and peer inside the window? Or is it just some sense of self righteousness you feel by being a good employee who wouldn't ever choose to work from home like those other lazy bums.
Wow, I must have touched a nerve. Actually, I semi-regularly work from home. My issue is with the people in my organization who take advantage of working from home, treat it like a three-day weekend, and will likely cause the work-from-home privilege to be revoked.
And my experience with coworkers is no different. I actually checked commit histories at some point to confirm that indeed most of those who worked from home on Fridays didn't produce any significant output. The sneakier ones would commit stuff, but clearly 'little stuff' that I sometimes suspected they had ready on a Thursday specifically to show something on a Friday.
Of course, you're completely correct that this doesn't mean that this is always the case. But if I were an employer, based on my experiences, I'd be hesitant to allow people to work from home on Fridays. Not in general, but specifically only on Fridays.
Cisco is a huge place and this varies by person/team/BU. Fridays a lot of people work from home.