Seeing the discussion here: https://forums.cardhunter.com/threads/custom-map-view-from-the-porch.4788/ followed by this new map: https://forums.cardhunter.com/threads/custom-map-floating-swamp-castle.4863/ in addition to my own use: https://forums.cardhunter.com/threads/contest-picnic-panic.3836/ it is clear that this is an issue that needs to be debated at great length.
Use them any way you please as long as it's consistent within the scenario. Anarchy rules in the strife-torn Cardhuntria and frequent perspective shifts in the optical interpretation of the seer-provided live pictures from the battlefield are only to be expected. It's quite natural it'd depend on the visual peccadilloes and predilections of the conjurer doing the transmitting. As engineers the worlds over know, the good thing about standards is that there are always several to choose from...
Replace "should" with "can" and we're cool. As far as I know, the only rule that can't be broken easily is the solid black line one for wall borders, and everything else is open for artistic expression. Any special terrain rules can be fun as long as they're well explained in the mission description (because they're out of the ordinary). I think that maybe the real question is what is out of the ordinary? a set of guidelines for standard shadow usage may help a map creator know when he's running the risk of doing something weird that might be seen as confusing. I know I tend to go overboard with mine, but that's just because to me it felt like a matter of artistic taste and nothing more. To me, the normal way of doing it looks boring. If shadows did something like "Marking areas as inaccessible" as a flat rule, then I'd have to rein in my liberal usage of them, but I don't believe that's a set rule we have to observe so I definitely don't.
