Okay…I think I get the intuition but the way you put it is really politically incorrect and backfiring. My below arguments are not on opposition to your suggestion, but just showing how your points can be interpreted/tinkered to give you a big hit. I will forward your suggestion to admin, as I feel your suggestion has some credit- especially for college and school guys during exam weeks. I personally know people who dont participate due to exams and fear of ratings declining. (Well, I dont, my zig-zag curve makes it obvious what my exam months are ). Now, back to why your points need improvement.
Less need to make fake accounts
Codechef doesnt allow multiple account in first place. Do you have one? IF yes, then do @admin knows? And yes, the rules state they will ban both accounts- we did so in past for many participants and will do so in future.
More value assigned to codechef ratings as they then fluctuate less.
The disadvantage you put is the killer for this point. Lets say a coder has good rating- how will you know he didnt “farm” it by abusing the proposed system this way? And afaik, we will have to make him declare that at start of contest- but codechef doesnt have registering option yet. You can estimate the time needed.
Since codechef is starting a Division system (as on the FB page) it is even more important.
Why? Can you please connect the points? “Fall from one division to another” is not a good argument.
The core motive of helping people learn gets strengthened.
I get your intuition for this- when theres no scare of ratings then theres a unique fun in participating in that contest. But it gets boring very soon. But since you said for occasional/once-in-a-while, it should be ok.
Less need for people to communicate solutions. I often have to discuss solutions with a participant who has AC'd the problem to know if my approach is fine. This shouldnt be required.
Controversy/Flame bait. This point can be crudely interpreted as “I discuss questions with others and I am publicly saying so. Do whatever you want to do.” (or in other words, some may interpret it as defying the rules. Some- not me.)