If vending machines continued to be displayed even when you walked somewhere where you could no longer see them (like blockers are) it would somewhat reduce the amount of pointless and tedious backtracking in the game. This is also true, to a lesser extent, of levers.
I know that there have been previous suggestions that vending machines also should appear on the map.
I wonder what happened to that suggestion thread that suggested that Vending Machines appeared on the Map? Cause I'm all for it.