It is an interesting build up to war, actually building up to war.

But it has been done before in history, frequently. In fact seige warfare also often required a surrender or terms prior to invasion.

Why put on the show? Putin would look weak, sending them home without having reached some kind of terms. They're in their court currently, and can do what they want. But by positioning them and camping them for combat, wouldn't it sooner cripple them completely if they don't react. Hey lads we're going to camp outside Ukraine for fun, watch the enemy, but dont engage, and now that we're all exercised on the border near the enemy, it's time to go back with tails wagging like good lil soldiers, into the closest for another couple of decades. Because Gaybears are lazy?