A very keen member of the specials, Andy's only sin is perhaps a cheerful over-enthusiasm for his part-time occupation.
Andy has equipped himself, entirely at his own expense, with a range of definitely non-standard weaponry, which is in every case far better than the one-size-doesn't-fit-anybody stuff the Watch give out. This includes what he describes to Samuel Vimes as "a new truncheon," which on closer examination turns out to be an Agatean martial arts weapon called a numknuts. Andy also comes equipped with two curved Agatean swords strapped across his back.
This has all led to his entering Watch folklore, as when he drew them in a single fluid overarm movement, a fellow officer named as Special Constable Piggle, who was standing next to him at the time, had to then be sent to Igor to have his arm sewn back on. In all fairness, Igor said it was a clean cut and he'd never done such an easy re-attachment, but this wasn't entirely the point...
Vimes is prepared to overlook a lot if the root cause is over-enthusiasm for the job, and in any case, "Two-Swords Hancock" has other uses for the Watch which stem from his day job as a Clacksman.