Our trip to Ukraine by car with Russian numbers took place in July 2017. Long thought whether it is possible to go on Russian numbers, is not too dangerous. Experienced for entering Ukraine, will not we create problems on the border with Russian numbers. We were told that it's dangerous to go, that the police (traffic police, DAI or what they are now called) will find fault on the roads. Moreover, they were going to go to Chernigov, and then to western Ukraine to Lvov.
Our observations and conclusions I told in the video "To Ukraine in 2017 by car with Russian numbers" • В Украину 2017 на машине с российским...
About our meetings with the police on the roads of Ukraine and the reaction to Russian numbers, see this video. In the first case, we just moved into Ukraine and after 30km we were stopped by the police. I apologize for the sound and forgot to turn the camera. The second situation is generally comical. This post is somewhere between Kiev and Lviv. In other cases, the police of Ukraine did not miss the opportunity to stop the car with Russian numbers, but politely and without fault finding they checked documents and wished a happy journey. One policeman explained that in the international movement it is necessary to have a diagnostic map.