I would really appreciate if you would share any findings regarding oil drops on the sensor, and hopefully it's clean. I'm sending mine in on monday, so I can get it back between weekends.
I really think you are far too worried about the oil drops. It is out of your hands, and even if a few of us have an issue (which I doubt will happen) what are you going to do? Worry about other things, and have confidence in Canon, don't spend so much time worrying about something you cannot control.
Hahaha, obviously you never had an issue with excessive oil from Canon before. The 1DsM3 oil issue threw so much oil around that everything was covered with oil, sometimes including your attached lens (not something you can clean yourself)! Having to send a body back in to Canon cost time and money so I think it is worth being concerned about. I don't think we should avoid having the fix done by Canon, but I am concerned about having my body come back clean until I shoot high speed and it throws over 1000 drops of oil everywhere. Given that consideration, I'll only send in my 1DX when I have the most down time. I'll also make sure my backup 1Dm4 body is clean and ready to be used full time.
You call it worried, I call it prepared.