This should not be a problem in a sane software development shop because there should be a way to track a) code reviews done b) tickets implemented/code merged /etc.
LOC/hour is a crappy metric for software development but averaging these over, say, six months should give some indication if someone is slacking off. Or just working in a different project than anyone else but task based variances ahould be accounted for. It does not give a "perfect metric" that could be used for perf evaluation but should be a sufficient safe guard against total slackers.
I would say that everyone is addicted to the thought that attendance == effort. It's just such an easy measuring stick to use when comparing the relative worth of two people.
<s> I mean, come on. That other lady might be "smart", but she leaves at 5, but I'm here until 6, so I deserve the raise, not her. </s>
This is very true. Personally I find that after a certain number of hours my ability to write good code and solve problems is significantly diminished. Although I would love Friday off personally I would find it more useful to finish at 3pm or 4pm instead of 6pm as that's when my productivity declines quickly. First of all that's a waste of my time in those final few hours as I'm getting much less done. But for the company I think if I had an extra few hours every evening I would be better rested and prepared for the next day and probably more productive in those first 6/7 productive hours.
I would be very happy to do 75% of my current work for 75% of the pay. Unfortunately things don't scale like that for a number of reasons. E.g. a team of 8 people working at 75% will not be as effective as a team of 6 people working at 100%. Coordination is costly, and the fewer people can get a job done, the better.
The overwhelming majority of people are in a situation where such a practice isn't possible. Jealousy is a very, very strong emotion, and leads to the crab mentality.
http://en.wikipedia.org/wiki/Crab_mentality
You see it in any sort of "someone has a better situation than me" post.
I would understand if I could work at top performance 10-12 hours a day, 5 days a week but that's just not possible for me. In the end driving developers to exhaustion is worse for everyone, with subpar code that'll probably require refactoring Monday morning.