But if you tell a bunch of thugs to do a job with ill specified parameters, and they try to solve the problem by harassing store owners, you can blame them for obviously going outside the bounds of intent, right?

You run a legitimate protection business. Of course you wouldn't extort money by breaking store owners' legs. ;)

Setting up a situation where there is risk of breakdown and structuring that situation so if the breakdown happens, all of the responsibility falls on the gig workers who lack the means to defend themselves and none of it falls on the company making all the money is an already understood pathology of the gig economy. Uber has spent so much time, effort, and money trying to convince legislatures and courts that they don't have any employees providing ride services for a reason.