The Russian leadership will do anything that they think that they will be able to get away with. They've done it over and over again and will not hesitate to push the envelop if it is their interest.
Have a read of
this
What makes you think that they were "pushed" into giving up their naval base on the Black Sea. Russia and the Ukraine entered into several agreements whereby the Black Sea Fleet was split and based. During the post Soviet era that fleet deteriorated significantly because of lack of funding. The leasing of facilities for the Russians to use in Sevastopol were extended until 2042 with an additional five-year option.
https://en.wikipedia.org/wiki/Black_Sea_Fleet While there was some dispute as to whether or not the extensions signed by the pro-Russian Yanukovych, there was no move by the new Ukrainian regime to oust the Russians who under the old treaties could have stayed until 2017 anyway. Russia's actions had much more to do with the Ukraine's recent more favourable view to engaging in economic relationships with the EU.
The discussions about Hungary, Czechoslovakia, Georgia, Poland and the Ukraine are clearly on-topic when discussing Belarus as it shows a pattern of behaviour by Russia that should be of concern to all former Soviet block countries.
:cheers: