As @terminus-nc said, it sort of depends on your state.
Washington has a section of administrative code that lays out minimums for linear and angular closures of field traverses for land boundary surveys, as well as a section which sets out minimum relative accuracy standards for “when positioning techniques used in a land boundary survey are not amenable to analysis with standards in WAC 332-130-090.” 0.07 USFt + 200 PPM @ 95% confidence.
In other words, satellite positioning methods are allowed for boundaries. And generally speaking, they should be, because a correctly performed GNSS survey in conditions appropriate for that survey will be every bit as good as a field traverse for the same parcel.
But, as to whether the average GNSS survey is being performed correctly? That’s a whole different question…and why I have a love/hate relationship with the local real-time network.
“…people will come to love their oppression, to adore the technologies that undo their capacities to think.” -Neil Postman