You would strictly have to be agnostic about whether there is a teapot in orbit about Mars, but that doesn't mean you treat the likelihood of its existence as on all fours with its non-existence.
Tendríamos que ser estrictamente agnósticos sobre la existencia, o no, de una tetera en órbita alrededor de Marte. Pero eso no significa que se considere la probabilidad de su existencia mano a mano con la de su inexistencia.