In this weeks parsha, the Jews got "bugged out" from their travels (for they had gotten so close to the holy land and it seemed that once again they were being led away), and they complained (21:4-5) the verse says that they spoke against God and Moshe, Our sages, brought down in Rashi, say that this denotes that they compared (made equal) the servant (Moshe) to his maker (also see more inferences from the rest of the verse). The Jews of that time are known as the "Dur Daya" - the Generation of Knowledge, a title given to them due to the extreme wisdom and knowledge that was attained by the nation, unparalleled in history. The lowest of the maids merited to high levels of prophecy. Even the most common folk were privy to high esoteric secrets of the Torah. So it is amazing to see that people of such high intellectual caliber, the mistake that they made was to equate Moshe to H"Y. This is the exact opposite of the way the (stupid) people of today think, considering the position of the Tzadik as minor and insignificant C"V. The nation was punished for their complaining, but it does not appear that they were even told off for their mistaken equation, for when they came to apologize (verse 7) they say to Moshe "we have sinned because we spoke against Hashem and You" which would lend it self to same inference as the above, that they are equating Moshe to H"Y, and yet H"Y accepts the apology and sends them a way to allay the punishment. From here we could learn that one is not so bad off for seeing the Tzadik as high as God. In fact we learn in Ethics of Our Fathers, that one is obligated to fear his Rebbe as he fears God.
That being said, I do not think that a mistake would have been went unchecked. When the Jews complained and spoke against God and Moshe, the name of God given is Elohim (this should not be pronounced, instead one can say Elokim), which is a name used in reference to the natural course of events that God allows to conduct the world. The Torah itself referst to Moshe Rabbainu as Eesh HuElohim, the Man of God, which our Holy Sages teach, denotes has power of God. For over this manifestation of God, Moshe Rabbainu had power. When the Jews apologized they mentioned the supreme name of God - YHVH. Originally the Jews made the mistake of associating their management expedient to Elohim, thus they equated the function of Moshe Rabbainu to H"Y in their management. When they apologized they made it clear that they now understood that their management was from H"Y - YHVH, on this Divine level there is no way to consider Moshe Rabbainu expedient what so ever.