Flightradar24 has a function that will pop up a notification if any plane in the world is squawking 7700. I didn’t think I would see much, but there’s about 2 a day, mostly from airliners, and mostly flying out of Moscow.
For instance, at this moment Aeroflot 1248, a 737-800 Moscow to Orenburg (REN) has put out an alert. It’s about halfway into a two hour flight at 31,000’ and 457 kts. Also Aeroflot 1404 from Moscow to Yekaterinburg (SVX) another 737-800 at 35,000’ and 466 kts is putting out 7700. I don’t see any flight path diversion for either.
Edit: Just now a third popped up. Aeroflot 1330, a Sukhoi Superjet 100-95b from Moscow to Arkhangelsk (ARH) at 35,000’ and 404 kts.
Does Russia use 7700 beyond our definition of an emergency?