I often bold portions of long quotes so that skim readers can pick up the important parts quickly. I find it cumbersome to note that this formatting is not from the original source, but at the same time, I don't want to unintentionally give some impression that was not intended in the original source.
What are suggestions for how to unobtrusively and neatly note that this formatting is not from the original source?
Is this actually important, or is it well-understood enough that emphasis formatting is often not from the original source?
Are there other options to bold and emphasis formatting that I'm not considering here?