rabbitoid: The basic problems with implementing features that the current implementation had not accounted for on creation, is the interaction with the existing system.
I felt the need to point out the holes in your algorithm, because you stated how "simple" it is and how "rubbish" is what others had said.

It is my estimation that the feature discussed here is implementable, but it is also my impression that the current system would need at least a partial reconstruction to do so, as the creator of the system had focused on other very important issues during the implementation(like versatility without compromising speed) and I have to say this site has the most flexible tournament system I have seen anywhere. Allowing unlimited players, variable-length sections, unlimited tournaments, a host of different time controls, different tournament types and so many things taken for granted by the people here really needed some very involved programming, considering all the issues you need to deal with in order to make it happen.

This does not mean that the integration of such a feature could not be done without reconstruction(as I can only guess as to current implementation), but extensive testing and very careful programming will be needed which I do not think is even near "very easy", even though the algorithm itself seems to be easy.

If you have not predicted that the need for games in a session to continue after a session is over may arise, you may need to expand the existing structure to allow that. Depending on where the structure is kept this can mean the need to rebuild the games database(again, wild speculation, and what I imagine to be worst case scenario).

So, contributing to the solution of problems and posting ideas is great, but I think it would be prudent to avoid classifications as to the difficulty of implementation for things we know very little(if anything) about.