For 1099 "employees", payment under $600 doesn't require reporting from the employer's side. It is still income to the one receiving payment. And it is not under $600 per check, it is under $600 total for the tax year per person.
Not sure about whether w-2 employees must be reported on for amounts under a certain threshold. I guess if there is no reporting then there is no w-2.
See disclaimer below.
Retired in 2013 at age 33. Keeping busy reading, blogging, relaxing, gaming, and enjoying the outdoors with my wife and 3 kids (4, 10, and 11).