Exactly the point ticket and organised travel and accommodations packages !
No need or demand for random scheduled services in reply to the thread openers original question
All visitors will be vetted in one way or another because just buying match ticket provides the authorities significant personal information about the buyer
They are so offering free or reduced domestic travel via the rail network between venues but that’s also with a catch of advanced ticketing and reservations again providing the authorities sufficient personal information about the movements and security of foreigners
Plenty of ways to keep tabs on who and where peeps are
Also the Russian intelligence will certainly be monitoring all foreign mobiles that make connections to their telecommunications network during these times
Seriously they WILL know a great deal of who what and where even before the traditional visible agents of law enforcement are considered