Even though it's GPL you should still read the code. It's very well written and educational. If GPL means you refuse to even read the code then I'm sad for you.
Technically if you read GPL'd code, you can't reproduce it as whole or in part under anything else but GPL (as this creates a derivative work). One of the reasons why some people take extreme care when dealing with GPL'd sources - one person reads it, then describes to others and they act on that.
Wrong, GPL is protected by copyright just like all the other licences, so as long as the reproduction is not verbatim but instead your own implementation based on the information you gathered while examining the code then there's no copyright violation.
Copyright violation isn't restricted to verbatim reproductions. I sympathize with eps. There are also a good number of people, believe it or not, who think that GPLv3 is too vague with its "distribution" criteria that a court could determine that it's effectively the same as AGPLv3. So if there's a policy not to use AGPL, which is fairly common because SaaS is an easy way to create the "secret money making sauce" of a business otherwise built on open source, GPLv3 will also suffer adoption.
eps' general concern is that this is entirely a court matter; the spirit of the GPL and sharing is meaningless to the law because at the end of the day there are only so many ways you can type "LIST_INIT(&new_sched->new);" and if a shitty programmer/programmer's company is suing you and has evidence you looked at that line of code that may be enough for a shitty judge to side with them. For similar reasons I don't have a habit of looking at patents (though that's usually because patents, even non-software-patents, are shit and obvious to the layman let alone someone in the field), but I do read (and have contributed to) GPL code.
And I am at -1 why? I actually worked with a couple of guys that did that, both from the OpenBSD camp. It looks weird and nerdy, but there are people who interpret GPL very conservatively.
