Some willingly go over duty time in places where supervision is less than stringent, especially if paid per hour.
Highest monthly total I've heard of is 300 hours, yes that's three hundred hours. DC3 crew flying sunrise to sunset every day for a month. At the end of it they looked like zombies and you would not have got into a car with one of them behind the wheel, let alone go flying. They did make alot of money that month though !
Could be done in a Dak due reliability, Carribou not so reliable and would breakdown.
Clue to operator: Mozambique late 1980s/early 1990s based Beira with DC3 and DHC4. I sure some can work it out.