[Analysis by Phil Simborg]
There is a simple reason Red should not double here--it's too easy a take for Blue. When it's too easy a take, that usually means that Red's winning percentage isn't high enough to be worth putting a weapon (the cube) into his opponent's hands, and/or it means that there just aren't enough "market losers" to warrant giving the cube. If Blue will take the cube on the next roll after most sequences, what does Red gain by giving the cube now? Very little. But what he can lose by giving the cube is significant if he happens to roll badly and Blue rolls well.
The take point at 4away/4away is around 20 percent, and as you can see below, given the fact that Red only leads the race by 7 pips and there is a possibility of leaving a shot or having an awkward bear in, Blue will win this game about 32 percent of the time. The "ideal" time to double is when your opponent has a tough decision, and here, it's a no-brainer.