Most of the companies I've worked for have been fairly relaxed about timekeeping. As long as I was seen to put in reasonable hours and got the job done, management didn't worry. The surprising thing is that when they did start to comment that it had been noticed (usually by staff/managers in other departments) I'd come in late a few times or taken a couple of long lunch breaks, I have always been able to show that I actually work longer hours than I'm supposed to, e.g. they'd comment that I arrived late Thurday morning and I'd point out that I worked an extra couple of (unpaid) hours on Monday!

Most managers are happy with this, although some still complain that they'd like to know when I'm going to be late - but since it's usually due to trains/traffic/etc, this isn't often possible.

The few places I've worked where they did try to insist on strict timekeeping had much lower morale and high staff turnover (as has been noted elsewhere). Somehow, most managers just don't seem to see the connection!