That's a good point. Anyway you look at it godmoding takes control away from the character's author no matter how minute, which is why it is a problem. Then the solution really would be to just set up a collaboration if you have a situation wherein you need to act a specific scene with a character that will span more then a couple of posts. That being said, you can't be collaborating on every other post so it comes down to judgement.

See, when I RPed before this almost every RP was one on one so I never really ran into this scenario. It was very rare that an RP included more than two people.