Before the battle of Hogwarts, many students were evacuated from the building. All underage students had to leave, and some students of age have left as well. These students were taken through the secret tunnel from the Room of Requirement to the Hog's Head pub, and Apparated away from there. The group was led by Madam Pomfrey, Mr. Filch, and prefects.
In chapter 30 of Hallows, Harry argues that
‘if Voldemort and the Death Eaters are concentrating on the school boundaries they won't be interested in anyone who's Disapparating out of the Hog's Head.’
and Professor McGonagall agrees.
After the students are led away, we hear very little about them in the novel. We know that Madame Pomfrey returns to the building, from which I think the Disapparition went without problems, and we learn that Colin Creevey sneaked back, probably even before he got Disapparated.
My question is, to where were all the evacuated the students Disapparated, and how safe they were during and shortly after the battle? Even if the Death Eaters are concentrating on Hogwarts, there could be some snatchers and other supporters of the Dark Lord out there hunting. During the battle, the army of the Dark Lord would probably notice how few students remained in the building, and might have the idea to leave and hunt them. They could try to capture the young students to use them as hostages to bargain with Hogwarts, thus gaining bargaining chips for the battle itself.
I'm worried about these students, so please tell me why I could know they were safe.