Ok, thanks benmachine. 
I'd understand if this 'feature' were overridden in later versions. The fact that (in the old system) these binds had no downside is something akin to how I made my crouch bind combined with my slow-walk bind. There was no reason not to do it as it gave crouch-moving the benefit of stamina regen. Similarly these build binds only have benefit. It's that sort of 'work-around' feature which IMO should be impossible to bind or else be a part of the standard system.
So long as we're on the subject, can someone give me an idea why the marked decon system can't be additional to the traditional decon? If it's just because of deconners then I put it to you that that is no reason at all. (If this can't be answered quickly enough to warrant the off-topic nature then I'll duly make a new thread for it.
p-q-qvm uses a combination of marked and non-marked decon:
You can decon as usual with the decon key but for the marked decon at least I use the console, look at the object in question and do /mark... which I should move into a bind possibly. ;-) I think this feature set is called "semi-marked decon".
What sucks about marked decon thus far is, that if you just want to move a building you can only do it outside the hitbox or outside the center of the building that you are going to replace (haven't figured out yet if it is the hitbox of the old building that interferes). So, for those perfectionists out there or if there is no other place to put the new building you can not do a "marked decon pixel perfect replacement move".
Also, if marked decon is the only option on the server getting those feeder nodes off the default base is becoming a pain in the ass.