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I'm currently reading Deathly Hallows. Once Voldemort's name has been Tabboo'd, it summons the Death Eaters, as well as breaking protective charms on an area (case and point, Harry's Tent).
When it is uttered, Death Eaters appear outside the tent in which Hermione, Harry and Ron are hiding.
Since the only requirement for Apparition appears to be a wand (no verbal cue to alert the Death Eaters) and Disapparating can be done extremely quickly (for example: Mundungus Fletcher in Hogsmeade, Dobby's death) - why don't the group just get gone and escape before they are taken to Malfoy Manor?