I feel like that "keep Looking" is a combination of you not being qualified for the job AND it would also negatively impact your loyalty. So, in terms of you chances of getting the job, it's exactly the same as "Not Qualified." At least, that's the way I look at it. That being said, I have often wondered if all "not qualified" jobs are the same. IOW, do you stand a slightly higher chance of getting a lower prestige "Not Qualified" (or Keep Looking), than a higher prestige "Not Qualified". Or if all NQs and KLs are the same percentage chance of getting them.
I, too, have always accepted that there is a small chance you could get a job you are NQ or KL for and it seems like I have read that somewhere.
This is, by far, the most thought I have put into it- so now I am thinking I might just start applying to 3 big time NQ jobs every season, just to see if I could ever get one, by luck.
EDIT: The more I think about this, the more I seem to remember that NQ jobs would kick your application back immediately and the KL jobs will consider you for a short period of time. Argh, I get more confused the more I think about it! :-) I can't remember.