Perros potencialmente peligrosos

[Perikles]

Is there a meaningful difference between perros potencialmente peligrosos and perros peligrosos ? In English, the expression potentially dangerous dogs is tautologous because dangerous means having the potential to harm, so the possibility is contained in that word. Potential is then unnecessary. This may seem like a quibble, but we are arguing about it here in Tenerife, where a child has just been killed by a dog, and where certain breeds of dog are classified as "perros potencialmente peligrosos"

Thanks.