It's not just that as a case - in 8 player games there will be many situations that you would have put down a defence boost that would be useful later on. Also, when you put down a defence boost it's usually if you want to hold out that border for a few turns. With this boost, this would mean that the oppertunist race would be a decent counter against this, preventing them from eating you up e.g. they start in a corner behind you, and you trap them there, they will almost definitely put a defense boost. It's also got the anti-troll factor, so I approve.
To make it more clean cut however, I think it should be a +20% boost. Also I don't like the name, Lopdo could probably come up with a halloween theme race though with that bonus.
+1, hope it becomes a race

The simple, the best.