Nah, Michael Schumacher will be able to do no wrong in Valencia.
If he wins or gets on the podium, he will be described as the greatest driver of all time (which is quite possibly true).
If he scores points, he will be praised for having hit the ground running.
If he finishes outside the points, it will be said that he put in a fantastic effort given the circumstances.
If he finishes last or retires, all the talk will be about how much the cars have changed since he last raced, how this was a new track for him, etc.
If he drives a clean race he will be praised for driving maturely.
If he takes a car or two out it will be said that he hasn't lost any of his competitiveness.
If he beats Lewis or Kimi, there will be asterisks placed next to their world championships to denote "without Schumacher".
Some people are saying that he has got nothing to gain and everything to lose, but I don't really see how he can damage his reputation at all.
I for one am looking forward to this immensely.