I use the term loosely to refer to Section-focused strategies where it's obvious that the goal is "Bolster early and outmuscle Infantry engagement". The actual number isn't as important IMO as to the BO where all early investments go to building more sections and upgrades and the ease as to which that can be done without being punished through good play.
Hmm, sounds like I ought to brush up on my camping behind sandbags builds (talking 3v3 here). Even today I go a two volks into two ISGs build, because the early UKF can shoot you off the field easily. So rather than take huge losses, just temporarily concede the field and then hit them with ISGs + MG.