To me it seems like kids just messing around, trying to either scare people or just make people say WTF? Or maybe just dabbling or showing off a little bit of esoteric knowledge they have. Not to say that they haven't inadvertently messed with the mojo of the house though. A good house cleansing wouldn't be a bad idea if one was to stay there...
It's an interesting mix of symbols and messages though. If there is any rhyme to the reason, the vertical triangles beside the door kinda seems hermetic in nature, "As above, so below". Maybe a portal?
When I was a kid, I worked at a gas station and we burned a pentagram into the concrete floor for giggles and shits. At the time it didn't mean anything to us other than a bit of fun.