if a terrier doesnt work below ground and stay untill dug its NOT a working terrier, lurchers ,hounds , springers etc hunt above ground and thats their job so they can be regarded as working dogs but a terriers job is below ground. that is WORK for a terrier , anything above ground for a terrier is sport, simple as that.
Sorry Dev,
But you are wrong if a terrier works it is a worker. If I work I am a worker it is as simple as that. Terriers were not initially bred to hunt below ground this was a trait brought in later. Work is work just because you dont rate it does not make it wrong