I suspect it's just a formality so they can increase the security around their base, without yet having formally requested authorization from their parliament.

I suspect it's just a formality so they can increase the security around their base, without yet having formally requested authorization from their parliament. In both international law and the law of many countries, there are substantial distinctions made between troops in uniform wearing their country's flag and those not. I don't think that there was any intent of being secret or saving face, just that because formal authorization from parliament hadn't yet been made, they couldn't move in under Russia's flag.