https://forecast.weather.gov/MapClick.php?lat=39.74&lon=-104.992#.Yg_IS5bMKrA

Even if The US has absolutely no intention of ever using these aircraft in the event of any hostilities (as it has publicly announced) it still exercises them publicly so that the Russians have to figure it in to their own preparations, complicating THEIR plans. Now, the Russians have to divert resources such as radars, anti-aircraft weapons, fighters and other assets from their missions in order to counter a potential US threat, even if it never materializes. Whatever anti-bomber defenses the Russians have to deploy will not be fully available to use against the Ukrainians.

Another aspect is to burden the Russians with the worry that the US is preparing a strike of their own, just in case the Russians invade any other country. It gives the US an opportunity to test Russian capability to predict, detect and intercept US movements, and forces them to reveal other abstract functions like radar frequencies, communications links, locations and preparedness of defensive facilities and so on.

Militaries are always engaging in this sort of thing, sometimes against their own allies! It tests your opponents and your own capability, and it gives you an opportunity to train your own people in realistic conditions.

In one exercise I participated in in 1968, the NATO fleet pretended to invade Norway, while the Soviet fleet pretended to defend it. Soviet ships and aircraft were everywhere, monitoring our activities and eavesdropping on our communications and testing our sensors. Soviet destroyers repeatedly sailed through our formations, sometimes deliberately interfering with our refueling operations or with the launching and recovery of aircraft, their submarines followed us, and their huge long-range reconnaissance planes flew so low and so close to our ship we could see their people behind glass blisters taking photographs of our weapons and electronics.

You may ask if these activities are potentially dangerous. The answer is yes. Accidents happened, and sometimes it was not clear if they were accidents.