The "matter within the jurisdiction" of border control is to inspect anything being brought across the border. You're not impeding that. You're simply not bring

The "matter within the jurisdiction" of border control is to inspect anything being brought across the border. You're not impeding that. You're simply not bringing something across the border. This is different from e.g. hiding drugs in your suitcase (or even data on a device): there you're impeding their ability to inspect those drugs.