Here's the Scenario.

Red is on the far left of the map, green is to his right, then purple, and then yellow on the far right.

In this scenario all 4 players have similar numbers of lands. Yellow's lands are the most stacked, but he is completely blocked in by purple, who has him surrounded with smaller stacks. As a result, purple flags yellow so that yellow doesn't kill him. Green follow's suit and also flags yellow.

The scenario hinges on red's actions. At the time, he has a fairly even fight with green and purple, but he has not flagged to red, who at the moment poses no immediate threat. When asked if he flags to yellow (who is on the other end of the map) he stays silent.

As a result of Red's silence, Yellow cuts through both purple and green, slicing them in half to reach red. Once yellow has reached red, red finally flags to yellow, and yellow accepts. At that point, the danger has arrived, and red cannot possibly fight all three players.

Now, Red has a much easier fight with green and purple as they're cut in half, and eventually goes on to secure 2nd.

So, has Red acted dishonorably by waiting until Yellow goes through green, and purple, or are these standard tactics?