Judging by the survey data, Lake Como lay fifty kilometers northeast of Milan, but that was only the straight-line distance.
There were many rugged mountain roads around this glacial lake, so they had to take detours. The actual distance was far greater than fifty kilometers.
Napoleon had outrun his enemies in Piedmont on foot with infantry. During the Battle of Mantua, the French force-marched for seven days. Napoleon rode three horses to death without sleeping before dealing Wurmser a devastating blow.
Setting explosives was not absolutely safe. Even a single spark could ignite the powder and cause a gun or cannon to explode before it was fired.
In short, Georgiana did not return to Milan until after dark. Everything in the city appeared normal; there had been no martial law or chaos just because she had vanished for a day.
The reason she had planned to return to Milan by carriage rather than teleport was that she wanted to see the castle north of Milan where witches had once been tried. But time had been so tight that there was naturally no time for a detour.
Dumbledore often lectured her about school rules—about enduring things first and taking revenge afterward, when one had supposedly already forgotten about them.
Not everyone was a forgetful fool who would forget revenge. But perpetrators were often the forgetful ones—or rather, they hoped their victims would forget.
There were things besides the Unforgivable Curses that could not be forgiven. Sirius had chalked up the "jokes" of the past to having been a foolish boy at the time, but Snape did not see it that way.
Draco had been attacked by Hufflepuff students on the train back to London in his fifth year. Aside from the grudge between his former allegiance to Umbridge and Hannah's group