A good question and it seems to be up to the Passport Control Agent at the time. The same as arriving to any country. You just never know what is going to be said or asked of you. Fortunately, arriving and departing Russia usually only involves a few looks rather than words

I have always Registered. I have never shown my Registration paper(s) upon leaving Russia and I have never been asked for them.
I suppose we can assume it has been entered into a Database for the Agent to see on her monitor? Perhaps this is giving the Russian Bureaucracy too much credit? I honestly don't believe that their collection and distribution of information is yet that sophisticated. I theorise this by reference to Lana's girlfriend, who is married to an Austrian. He has never Registered at any time visiting Russia.
The only three things that Passport Control seems to worry about is your Passport, Visa and Stamped Immigration Form.
I'm not giving anyone advice to Not Register. I always Register in respect of 'Finagle's Law'..... "Anything that can go wrong, willat the worst possible moment". I like things to go smoothly whenever I'm in Russia.... especially when arriving and departing!
