Blizzard Entertainment was forced to suspend Crimean accounts in order to comply with United States sanctions against Russia and Russian-occupied Crimea. This blockage affects any game in the Blizzard franchise that requires a Battle.net connection, such as hearthstone, Diablo III, World of Warcraft, etc.
Crimeans with an account received an official notification that states:
"You are receiving this email because, in accordance with current trade regulations relating to the region of Crimea, we are legally required to suspend access to your Battle.net account. Any recurring subscription payment will be cancelled."
The current trade regulations that Blizzard complied to come from the most recent sanctions from Executive Order 13682. This is in conjunction with the company's Terms of Service changes (around 2012) that requires them to obey any government sanctions. Executive Order 13682, section 1 a (iii) states:
Since the United States is doing everything within their power to cripple Russia, the latest sanction was placed to include as many U.S. based businesses. "[...] services, or technologies" are vague enough terms to give any U.S. business pause.
Several other companies had ceased services before Blizzard began their Battle.net suspensions. Apple, Google, and Paypal were among the first, while Valve was one of the first game provider to block access to Steam and Steam library earlier this year.
This isn't an unprecedented event.
Blizzard Entertainment has already felt the effects of U.S. sanctions before. The Iran sanction "amendments" in 2012 did cause a few issues for them. When the additions went through, Iranian players discovered they were locked out of their accounts and access to the Battle.net sites.
Those fans took to the forums in hopes of a fix, but quickly discovered that with the new U.S. sanctions, they would not be gaining access back to their accounts any time soon.
This Agreement shall be governed by, and will be construed under, the laws of the United States of America and the law of the State of Delaware, without regard to choice of law principles.
Thankfully, the Iran sanctions are slowly being phased out as negotiations continue, meaning Iranian players could gain access to their Battle.net accounts in the future.
But Crimea is just at the budding stage of conflict and will have to endure the restrictions for quite some time. Blizzard Entertainment went on to apologize to those affected: "We are sincerely sorry that you're being impacted in this way; if the situation changes, we will happily do our best to restore access to your account."
Sadly, the region of Crimea has returned to being the rope in Ukraine's and Russia's tug-of-war. Crimean players will not have access to Battle.net and other U.S. services until their situation changes. For so long, Crimea has been a region of either Russia or Ukraine.
Either way, Crimea could return to some normalcy and sanctions could then be lifted from the region, returning many players back into Blizzard Entertainment family. Sadly, political issues will continue to cause trouble for the gaming community. One can only hope that the future will be brighter.