"Could you elaborate on the ways that you feel it has been, Celebrim?"
Well, not in detail. I am in fact making a supposition, so take it for what you will. I don't sit in WotC marketing rooms, and I haven't opened the sealed section of Dragon 300 - I've only 3rd hand report of it.
From what I have heard, there is a very very small portion of that sealed section that even needed sealing. For example, there is supposedly a section on monster cults that is more or less identical to a section on monster cults that went by some months ago without even blinking the eye, nor did it sound significantly more evil than the Drow issue that went by the month before. Mostly it was gross out along basic squimish horror themes, and most of it doesn't sound any worse or darker than what Dragon traditionally does in October issues.
So ask yourself why would the editor chose to go to the expense and trouble of a sealed section for the sake of say one paragraph worth of potentially contriversial text? Does he not in fact think that that sealed section will actually pay for itself in some fashion, and if so by who? Surely he (or she) doesn't think that the folks at Barnes and Nobles will be carding the kids that buy Dragon magazine? Do you imagine that he thinks it is really people like me, 20 years in the hobby, plenty of real world experience, that are intrigued by the contents of sealed sections of magazines labeled 'mature audiences only'?
No, I imagine he (or she) remembers what it was like to be 12 (or 15 or whatever), and courious, and full of yourself, and rebellious, and desparately wanting to be cool and grown up, and thinks 'A sealed section labelled mature'. Now THAT would be a good marketing ploy. And it is, of course. And he even made sure that most of the section wasn't all that contriversial on the whole so that Dragon wouldn't garner a whole lot of negative attention from the Public Library curators that put in the kids rack and the christian right in general etc. So if that is so, why Corpsebond? Well, because you got to sell that big WotC book coming up, they are one of your main advertisers probably, and if there wasn't something completely _VILE_ in the sealed section, the hopes of the drooling fan boys would be crushed. They'd actually realize this is kiddy stuff for the most part. And face it, 9 times in 10 that anyone labels anything 'mature' or 'adult', it is appealing to the purient and baser emotions anyway.
Fairy tales are mature. Bugs Bunny cartoons are mature. 'Wall of Maggots' is not. Pornography is not. I wonder what we are getting BoVD? Since you mention him, I have to wonder whether Monte himself even wanted his book labeled 'mature'.