El peligro es que cuando un piloto recibe uno de estos servicios, él y el controlador tienen que aceptar ciertas reponsibilidades y obligaciones referente aviso de tráfico, cambio de nivel o rumbo, y aviso de terreno
As the airspace in question is uncontrolled, there is no doubt whatsoever as to who is responsible for traffic and terrain avoidance. And contrary to what you seem to think, the pilot is not obliged to report level or heading changes, although if in receipt of a service (which he is similarly not obliged to request) it's obviously in his own interest to do so.
In any event,
CAP774 has all the answers you need.
Asi hay el peligro que un piloto va a recibir un servicio de ATC Gibraltar
Doubt it. As soon as they hear a Spanish accent on the radio, they chuck them over to Seville Information
(and that would not be you, by any chance?
)