Not at all. It is true that the magnetic fields created by the LHC machine and its experiments are very intense, but they are localised and contained. The machine's magnetic field is especially well contained within the accelerator. Even in the case of the experiments, the intensity of the field is very weak just a few metres away, and it decreases exponentially with distance. Since the magnetic fields are produced 100 metres underground, they are undetectable on the surface.