Lazamataz: We are 98% Soviet Union now.
In old USSR one needed a passport (or a photo ID, issued by many employers and bearing minimal security features) to buy airplane or inter-city train tickets. I don't know what was the purpose of that since the ID was never checked against a database and tickets were sold to anyone. Probably that was a leftover from Stalin's times, where a citizen was essentially confined to his prescribed area for life and work. To compare, in the USA today a person needs an ID to buy alcohol or tobacco - that was not required in USSR. The internal passport was simply a standard ID that everyone had, an easy thing to ask for and to check. The USA is probably unique in the world in having no way for a citizen to prove that he is a citizen. It is not necessarily an advantage. Currently the USA uses SSN and driver's licenses as IDs, but they are not reliable (just look at the President if you can take the pain.) Canada, for example, issues citizen IDs (a plastic card.)
Travel as such in USSR was not restricted since Stalin died in 1953. Certain areas of economy actually depended on mobile workers. There were no searches on roads (except if the police was looking for an escaped criminal, I guess.) One could drive from the border with Poland all the way to Vladivostok, as long as your SUV can take it. There were no searches anywhere else, as matter of fact, unless a police officer is arresting you for a reason.
If this story is true then we are already less free than in the old USSR. The only freedom left so far that USSR couldn't match is the freedom to leave the country. But as we know the government is working on restricting that and making a passport into a privilege.
Also note that USSR's requirements for an "exit visa" were also supported by near impossibility for a common Soviet man to get an entry visa into any country that is worth visiting. This can happen to US citizens overnight - as soon as they are no longer welcome abroad.
“In old USSR one needed a passport (or a photo ID, issued by many employers and bearing minimal security features) to buy airplane or inter-city train tickets.”
You need to show ID to buy an Amtrak ticket these days.
You may be asked to produce ID when the conductor on the train collects your ticket.
I know, I used to work there (now retired).