Why do modifiers have to be used directly with blocks

[crazyjaw]

The http://getbem.com/naming/ bit on modifiers says this is "Good":

<div class="block block--mod">...</div>
    <div class="block block--size-big
        block--shadow-yes">...</div>

Which implies that you must always have the block directly along with the block--mod, and being a child of a block doesn't cut it.

I dont have an understanding of why this isn't acceptable:

<div class="block>...</div>
    <div class="block--mod">...</div>

[tadatuta]

Is this an answer to your question?

[crazyjaw]

hmm ive seen that, and it doesn't address it directly (seems to talk about class="block block--mod" vs class="block--mod", rather than the nesting bit, which actually makes sense to me)