1) If we have registered for a contest and enter when the contest starts and look at the problems, but not submit any solutions, are we still rated? Do our ratings change?

2) Suppose, we don't register for a contest but directly enter it, DURING the contest, and submit solutions for any of the questions. Are we still rated and do our ratings change? (PS: I know that if we haven't registered, but enter just to look at the problems, our ratings don't change. Question is what if we don't register, but still enter the contest and actually submit solutions)