Or Dumbledore can be carrying the Stone on his own person all the time, because even though Flamel insisted it be in Hogwarts, 1) the strongest protection the castle can offer is an ‘adult wizard’, in Quirrell’s terminology, 2) it is inconsistent with Dumbledor’s morals to set up a scenario in which a student can actually die, no matter how possessed, 3) canon!Dumbledore said once that he only took the Elder Wand to protect others, but not to rule, and that would be a nod to Rowling, 4) if he knows the wards have been tempered with, then it is at least weak evidence that Voldemort (or whoever in the castle can speak to snakes and has the Crown) has bluffed and the Stone, after a while, can be returned to Perenelle...
Or Dumbledore can be carrying the Stone on his own person all the time, because even though Flamel insisted it be in Hogwarts, 1) the strongest protection the castle can offer is an ‘adult wizard’, in Quirrell’s terminology, 2) it is inconsistent with Dumbledor’s morals to set up a scenario in which a student can actually die, no matter how possessed, 3) canon!Dumbledore said once that he only took the Elder Wand to protect others, but not to rule, and that would be a nod to Rowling, 4) if he knows the wards have been tempered with, then it is at least weak evidence that Voldemort (or whoever in the castle can speak to snakes and has the Crown) has bluffed and the Stone, after a while, can be returned to Perenelle...