This was true before I was a moderator and is still true. If I modify a post of my own, the "email me new replies" checkbox is *always* checked. If I uncheck it, save the modified post, and then decide to modify it again, the box is checked again.
If I don't remember to uncheck the checkbox every time I modify one of my posts, I get an email every time anyone leaves a post in that topic (potentially, about 100,000 emails).
I'd say that I modify at least 30% of the posts I leave, often more than once. I estimate that I've unchecked that little box at least 5,000 times -- probably closer to 10,000.
I'm begging you to let me stop having to do that.