Please turn CAPTCHA checks off for my comments on blogs I have publishing rights for!
If I own or co-author the blog, I could post anything I wanted in the main body of a post anyway, so whether I'd be able to splog links all over the comment section of it or not just isn't interesting; it's just a waste of time, and a waste of my time having me type in CAPTCHAs.
If I'm logged in as a blogger user, you know if it's my blog or not, and if it is, you know it's silly to prompt me with the CAPTCHAs under these circumstances. So please don't. Or make it a blog owner's option not to, if you have some odd use case in mind where they would actually be appropriate and useful. But I warmly suggest having that option turned off by default.