It ain't.How the hell is chapters a WPN?
...But they are the biggest book retailer in Canada, and I'd wager they contribute significantly to D&D sales in this country. It's probably important to WotC to keep D&D in big-box stores like Chapters, so I suspect WotC not about to pick a fight with them; WotC looks the other way, and both companies profit from Chapters breaking the street date.