Territory part 2

In several movies and books vampires put a mark that only they can see on things. So like if they have a safe house they mark it so other vampires can use it in need. Or if it's an enemy vampire they know to stay away. It's very similar to the idea of animals peeing on something but doesn't smell so much. The thing is usually they say well it's in a spectrum humans can't see in. Well with all the technology around you would think that the occasional human would stumble across a random mark here or there. Plus it depends on other vampires knowing what your symbol is. If no one knows you does it matter who it belongs too. Status is very important when it comes to marks. If a vampire sees your symbol and knows what it means but doesn't respect your name they might decide to use your stuff anyway and tell you where to stuff it. The system of individual marks just seems very complicated in comparison to the peeing thing.