Plot hole: The cable Emma dangles from is secured to a safe deposit box by a powerful electromagnet rigged up by Ash. When he turns off the power, which he will have to do (they can't leave the cable and magnets in place!), the whole rig will drop to the floor, setting off the alarms. Even under tension, it would be impossible to wind in the cable and magnet fast enough to stop it dropping, and there is no sign of any sort of mechanism that would allow them to try to do that anyway.
Hustle (2004)
1 plot hole in season 6
Starring: Robert Vaughn, Robert Glenister, Adrian Lester, Rob Jarvis
New Recruits - S5-E2
Factual error: The contract Stone and his team force Carlton Wood and Harry Fielding to sign guaranteeing Fowler's widow the royalties from his invention for life is signed under duress and is therefore invalid. It is hard to believe that none of Stone's team know this, but it is impossible to believe that Carlton Wood wouldn't.
Mickey 'Bricks' Stone: Albert, what the hell were you doing in a church today?
Albert Stroller: Gil Stewart died this afternoon. I was there at the end.
Mickey 'Bricks' Stone: Oh God, I'm so sorry Albert. You two were like brothers.
Albert Stroller: We worked Vegas together. That man was made for bright lights. Poor bastard - died of a stroke in a dental surgery.
Mickey 'Bricks' Stone: Well, someone should sue them.
Albert Stroller: Aye, he was pretending to be the dentist.
The Hustlers News of the Day - S3-E5
Trivia: In some versions of this episode the name of the newspaper the grifters con has been rather clumsily dubbed over as "The Weekend World" rather than the original "The Sunday World", which is a real newspaper.