Hrqls: I wasn't really thinking about tournaments when I gave the suggestion. In non-turnament games you can start if you have x or more available slots, and the number of games will never increase during the match - only decrease. So the limited number of game slots shouldn't be a problem.

For tournaments it could start as many games as possible within the membership limit, and fill it up as game spots becomes available.
Or simply limit the feature in tournaments to certain membership levels.

Btw., the suggestion is meant as an option when creating the match, not as a replacement of the good old way.