I am planning to visit Saint Petersburg alone for 4 or 5 nights and stay at an AirBNB. Now, I am obtaining my invitation via a travel agency. I am not sure if they can register me once I arrive in Russia, but my hosts have declined to register me upon arrival. Some also claim that since I am going to stay for less than 7 days, I can choose not to register myself.
But just to be safe, how does one register himself if the hosts or the agency are not going to be of any help? In such a case, how do I exit the country or deal with police if stopped, if I do not register myself with the Federal Migration Services?
UPDATE:
Just got back. I did not have to register since I stayed for 3 business days and 2 holidays (Saturday and Sunday). I was not asked anything on exit but handing the Migration Card which was given upon entering the Russian Federation. Hope this helps future travelers.