It's probably a toss up which is more annoying to knitters: knots in wool or errors in patterns. We're told that three knots in a ball of wool is the acceptable industry standard, altho' I'm not sure the industry's ever run that by a group of knitters. (Justification is that without the knots the wool would be way more expensive.)
Anyway, I don't really know why I'm saying that seeing as I know nothing about it. On the other hand, I have lots of experience of mistakes in patterns. What do you do when you find an error? Sometimes you can easily work it out for yourself. Or you can fudge it; I'm a pretty good fudger. You could go online and see if there are any published errata. You can look on ravelry at the finished projects and see if other people had the same problem and how they solved it. Or you can post in the ravelry Patterns forum for advice. If all that fails, you can contact the designer, either through ravelry or via any other means you have.
So, when I had a problem last night with a pattern - having gone through all the other possibilities above first - that's what I did. I sent a polite rav message asking a very simple question. I got a quick polite answer referring me to Rowan, as, altho' the designer had designed the jumper, Rowan had published the pattern in one of their collections so the responsibility for problems was theirs. Well, no point in contacting Rowan seeing as I'm (legitimately) not using the yarn of theirs that the pattern was intended for. And that got me thinking.
Following the money trail, which sadly is what this is all about, I'm guessing this is how it worked. The designer was presumably paid by Rowan to design the jumper. Then Rowan published the pattern as one of their own. So, the designer was paid but got no further cash from ongoing pattern sales; Rowan paid the designer for designing the pattern and then kept the payments from sales. (This is, as I said, all guesswork...) So they've both had their financial reward for their own parts in the pattern production, but it seems that, although I paid for my 'free' copy through the subscription I had at the time to Let's Knit, (who put it in one of their supplements), when a problem's found in the pattern there's no one to help. Doesn't seem right, does it?
I have some sympathy with the designer - why should she support patterns she's assigned to Rowan? And this pattern's fairly old now - how long should designers be obliged to offer support anyway? (This pattern appears on the designer's rav page so I'd say at least as long as they list it among their accomplishments, but that's just a personal opinion.) I have some sympathy with Rowan - I'm not using their yarn and, from their point of view, I got the pattern for nothing.
Okay, I can manage without help but what about the hapless buyer who doesn't regard a pattern as necessarily supporting a particular yarn. For many knitters a pattern is just a stand alone purchase - they're not interested in anything beyond whether it's for DK or aran. And really, why should they be? If there's a mistake, it's a mistake, whatever kind of wool you're using.
This is what really struck me though. On various ravelry forums, wool shop owners are encouraged to help everyone who comes through the door with a problem, no matter where they bought their supplies or whether they've ever darkened the shop doors previously. It's good to help people, I personally like a bit of problem solving and, from a business point of view, there's always the hope that if you treat people nicely they'll come back and buy something. The equivalent for me would've been that designer just taking a minute or two to say either: yes, it's a mistake, just try adding a few more stitches to the buttonhole band, or alternatively: nope, you've misunderstood this bit here which is where all your problems started. I'm sure it would've been a really quick fix for her and would've left both of us with that warm glow of gratuitous helpfulness. And then, in future when I saw her patterns, instead of thinking: well, I'm not using that because there were issues with the last one I knitted and she wouldn't help me, I'd think: yippee, this designer's so nice, I'll buy this one because I know if I come to grief she'll help me.