Question on crosswalks, inferred vs. mapped ones

I just started today with a local install. It all went smooth, importing my city. Main interest is pedestrian routing. Here crosswalks (highway=crossing on nodes) are meticulously mapped. The heuristics though infer a lot of them, where there are in fact none. While those in places where there is no crossroads simply are missing.

Is there a switch, to have (only/all) mapped crosswalks appear? Just switching off heuristics, would that result in no crosswalks? Will that be very complicated, to combine intersections etc. with mapped crosswalks only?