I'm glad my topic was able to create some good discussion. I hope it can keep going.
In general (and I'm not an architect, just a "fan"), I'd generally be opposed to building a bunker if it served no other purpose than to help align someone. I'm not opposed to helping people align, though, nor am I opposed to occasionally mis-aligning people, either. Everything in balance.
So I wouldn't ever have a rule, were I an architect, to not have an "aiming bunker" per se, but if the bunker served another purpose or two, then I could see doing it occasionally. Or using a tree, or a distant landmark, or something else at times, too.