that really doesnt help either, as one can put down either wood doors or metal doors between the pillars not allowing you to escape... so pillars dont help..
the only thing that I have seen that helps me keep my doors protected is to build on somewhat of a slope not much of a slope but enough..
put down a foundation and see what side cant have another foundation on that side and make that your door side, since they wont be able to put down a foundation nor can they put anything else down that isnt indestructible, the only way they will be able to grief your doors is to put down storage box's/ small or large, Barricade's and possible one of those small huts but they decay pretty quickly..
best of luck man
He means to put down individual unconnected foundations as close to the perimeter of your house and as close to each other as the game lets you without connecting them. That way, there's no way anyone can put down foundations between your house and the barrier foundations, they can't connect the individual foundations themselves, and they'd have to go quite a long ways around the barrier foundations to wall you in.