They can certainly find out. Just like ethically sourced coffee beans are a thing; ethically sourced menial labour can be a thing. It's hip and cool to use ethically sourced labor that isn't toxic to the society you live in. :-)
1. Federal poverty level isn't a term [1]... >The poverty guidelines are sometimes loosely referred to as the “federal poverty level” (FPL), but that phrase is ambiguous and should be avoided, especially in situations (e.g., legislative or administrative) where precision is important.
2. Government instructing market isn't in the constitution, nor is it in Free Market Capitalism, nor the concept of a Democratic Republic...
With dignity implies; not starving, not being housing insecure, not being unable to afford health care.
Note that it does not imply that you can afford a vehicle, television or an internet connection; although the latter might be worth adding to the former.
I personally think that companies that deliberately structure employment relationships to deny workers full-time status should be pursued as tax evaders.