I agree the double hyphen looks odd, though I also think it's the most logical. "Anti money-laundering systems" looks a bit odd with the anti on its own, while "anti-money laundering systems" suggests the laundering of anti-money. Okay, time to apply reality over logic, this isn't sci-fi so anti-money isn't a potential confusion.
I'm now pondering the same question with "a mid single digit number". Why can't these people be like everyone else and just say "in single digits"! Guess I'll go with "mid-single digit number" on the same basis. And use of non-breaking spaces.