Georgia didn't move first. Russia moved first.
The existing situation in South Ossetia was that Russian troops and Ossetian irregulars patrolled the Ossetian villages in South Ossetia and that Georgian soldiers and Georgian police patrolled the Georgian villages in South Ossetia.
Almost two weeks ago, this uneasy, unspoken agreement was breached when IEDs were set off killing Georgian policemen on their routine rounds.
This was followed up by artillery shelling of Georgian villages from artillery emplacements in Ossetian villages.
It is clear in retrospect that these IEDs and this shelling was not simply the work of overeager Ossetian irregulars, but a deliberate provocation by Russia - which quickly mobilized forces to the Georgia border within hours of Georgia initiating some retaliatory shelling.
Russia escalated and Georgia reacted - not the other way around.