Comment by its-summertime

There is training systems and validation of skills in mturk iirc: for tshirt folding, you'd be given fake setups to be able to get used to controlling the robot, if you can't do it, you won't ever get assignments to do it. For traffic overrides, you'd be tested on having correct knowledge, and once again given supervised tasks to show you can actually be trusted (and there would be safety systems, elevating tasks that can't be performed at your level to people who can, etc)

The worker needs to do a bunch to opt into any given work group, which makes the (lack of) payments extremely unreasonable on top of everything else