It might help, but drug dealers are pretty resourceful.
England has seen people using Fixed Odds Betting machines to launder money.
http://www.theguardian.com/uk-news/2013/nov/08/gambling-mach...
> James, 24, looks like just another lost soul in the high street, shuttling between the six betting shops in an east coast seaside town. It's a weekday morning and if you catch up with him inside a bookmaker, you'll find him peering intently into the green glowing screen of an electronic gambling machine – feeding in £200, "a score at a time".
> But this is not a young gambler blowing his meagre wages. James is a drug dealer and his interest in the bookmakers – and the fixed-odds betting terminals (FOBTs) in each shop – is all about laundering money. "That's what turns dirty money clean," he says. Dealers feed their drug money through the machines, losing a little and then cashing out with the vast majority of their stake, James says. They can then collect a printed ticket showing they have gambled that day – meaning that if stopped by police, they can answer questions about why an apparently unemployed young man carries hundreds of pounds in rolled-up cash.
> Earlier this month the Gambling Commission, the industry regulator, fined Coral bookmakers £90,000 in profits it made from one drug dealer who had laundered almost £1m in its shops.
I don't think the gamblers care. It's unlikely he was feeding £50 notes into the machines, but £20s and £10s.