I have always liked the idea of medieval mapmakers using the phrase "Here Be Dragons" to denote unexplored or dangerous territories. Sticking a fire-breathing reptile in documentation when you run out of facts? That’s panache. These days, people aren’t so stylish. When an information architect (or user experience designer) doesn’t have the time (or the talent) to document content requirements, they stick a "page stack" on their site map.
Sitemaps are common deliverables, desired by clients who want a visual representation of a site. Since they are rarely used to make decisions, information architects may not consider them the valuable tools they are. The effort required to make and maintain them requires time that might be better used elsewhere. In fact, I would suggest that making sure the little boxes line up is a waste of an IA's mental abilities.