I think that makes sense; technically, the time spent browsing the net for resources would take away from development time for other aspects, essentially balancing it out.
It would be pretty obvious to state that doing anything inside the editor for the project would be illegal, but that doesn't necessarily include things like sprites, scripts, or music. Those three are kind of a grey area. It is totally possible to work on those things without actually "working" on the project files themselves. The main reason I asked about this was because I was preplanning for it and had some old unused sprites I made that I thought would fit for the project. I could right now start making tiles for my game, and not have opened up RPGMaker at all, so does that make it legal? And technically, it might not matter at all because once the "theme" is announced, all that I did could be void anyways.
This discussion probably isn't going to get any results in terms of an actual answer, though; we kind of have to wait for a more "official" response from the organizer.
You've lost me how did messing with the editor itself come into play?