We should not forget that the railway sheds and lines at TOC, Prestwick and Troon are NOT part of the courses, being OB. The numerous stone walls at NB West ARE on the course, of course. I think that in this current age, the liabilty issues of designing a golf hole in which a public throughfare was in the possible line of flight of a golf ball or a stone wall was constructed that might lead to a ball bouncing back and injuring a player would make such architectural features (not "hazard" viz. The Rules of Golf) impractical.