Fairly certain that this happens all the time
It does, yeah.Although Russia has been greatly increasing the amount of fly-overs it has had over all nearby countries in the last year.But they're just chased off every time. Our aircraft always intercept them quickly.
Eh, it's nothing to worry about and America probably does it to Russia just as much as Russia does to everyone else.Now, if they managed to sneak some nuclear submarines past our coastal defences and surface off the coast of cornwall then we might have a problem.