C56 There Is a Treasure Chest No One Is Looking

Certainly, if a giant serpent were to appear in the Forbidden Forest, the centaurs would undoubtedly take notice and promptly inform Hagrid, which in turn means Dumbledore would be aware of it as well.

Lord Voldemort, naturally, would avoid such a scenario. Hence, he would ensure Nagini was concealed near the Forbidden Forest in a secure location