You can use things like lava and water sigils in other users claims

Not sure if I should be reporting this on blood magic instead?

Like half the mods in the pack can bypass claims. Building gadgets, a server had to disable those because they can place and destroy anywhere. AE2 matter cannon, can break blocks. If you can surround someone's base (up to 128 blocks) with AE2 spatial pylons and have a huge amount of power you can just yoink someone's entire base.