Weary,
My favorite sector in Atlanta Center was the WILKES sector in western North Carolina (NW of KCLT.) It was really nothing more than an Approach Control in airspace that wasn't busy enough to justify having it's own Approach Control. It was 80 x 100 miles at 10,000 feet and below.
Anyway, at the Centers in the States we have MSAW -- Minimum Safe Altitude Warning. It is based on the MIA --- Minimum Instrument Altitude (which is slightly different than the Minimum Vectoring Altitudes used by Approach Controls.) If the aircraft descended below the MIA the datablock would blink on the scope. I think it was quite effective.
The alert could be surpressed and the parameters were locally adapted. Atlanta Center got its hand slapped when it was discovered that it had the MSAW suppressed within 50 miles of the destination. I think they changed it to suppress the alert within 10 miles of the destination airport.
Nuisance alerts could be a problem. An aircraft shooting practice approaches at an airport other than its destination could make you nuts.
Between that and the Conflict Alert on VFR traffic, I've seen a half dozen data blocks flashing all at once. But all in all, I think it was a desirable feature.
Don Brown