e: Huh, I just figured out a variant of LBF: Instead of triggering seals based on people crossing the chakra barrier, it triggers seals based on it breaking due to distance from other such seals. To get this to work we'd need to work out a single "source" seal that the LBF variant constantly detects distance from, and if this distance is exceeded, it triggers an attached seal.
This would allow Kagome and Keiko to throw explosives freely among allies, for one thing (though his shaped charges would still be dangerous). I'm sure we can think of other uses for it, too -- drop a storage seal with a stupid box in it behind you, and then just keep running, for one.