I could be mistaken, but I think the idea is you only have one h1 per page. If you use an h1 in different contexts on different pages, the rules for those pages should probably be in different stylesheets as well, obviating the need to qualify them.
In HTML 5 you can use the h1 element multiple times. For example, lets say you are writing an article
article
h1
h2
That is perfectly valid, now lets say you have an header that gets added before each article that contains some information such as author, time created/published
header
timedate
h1
Article Title
author
article
h1
h2
