Through clearances are handy for places that are really IMC, and in controlled airspace, and has poor radio communication from the ground. Those are usually mountain areas, but any airport that doesn't have line of sight to the appropriate RCO/RCAG radio site.
Yes, a "one-in-one-out" type airport will be shutdown the whole time you're on the ground, but most really rural airports just don't have much traffic to worry about.
I've issued a few "through" clearances, and I don't recall there being an issue. But, then the pilot requesting / filing that hopefully knows what he's doing.
If not, there's provisions for that, too. Shut down for 30 minutes, and then notify aircraft for the next 30 minutes of an overdue aircraft.
http://www.faa.gov/air_traffic/publi...c/atc0402.html
4-2-6. THROUGH CLEARANCES
You may clear an aircraft through intermediate stops.
PHRASEOLOGY-
CLEARED THROUGH (airport) TO (fix).
4-2-7. ALTRV CLEARANCE
Use the phrase “via approved altitude reservation flight plan,” if the aircraft will operate in an approved ALTRV.
PHRASEOLOGY-
VIA APPROVED ALTITUDE RESERVATION (mission name) FLIGHT PLAN.
NOTE-
An ALTRV normally includes the departure, climb, cruise, and arrival phases of flight up to and including holding pattern or point/time at which ATC provides separation between aircraft.
REFERENCE-
FAAO JO 7110.65, Para 4-3-3, Abbreviated Departure Clearance.
4-2-8. IFR-VFR AND VFR-IFR FLIGHTS
a. Clear an aircraft planning IFR operations for the initial part of flight and VFR for the latter part to the fix at which the IFR part ends.
b. Treat an aircraft planning VFR for the initial part of flight and IFR for the latter part as a VFR departure. Issue a clearance to this aircraft when it requests IFR clearance approaching the fix where it proposes to start IFR operations. The phraseology CLEARED TO (destination) AIRPORT AS FILED may be used with abbreviated departure clearance procedures.
REFERENCE-
FAAO JO 7110.65, Para 4-3-3, Abbreviated Departure Clearance.
c. When an aircraft changes from VFR to IFR, the controller shall assign a beacon code to Mode-C equipped aircraft that will allow MSAW alarms.
d. When a VFR aircraft, operating below the minimum altitude for IFR operations, requests an IFR clearance and you are aware that the pilot is unable to climb in VFR conditions to the minimum IFR altitude:
1. Before issuing a clearance, ask if the pilot is able to maintain terrain and obstruction clearance during a climb to the minimum IFR altitude.
NOTE-
Pilots of pop-up aircraft are responsible for terrain and obstacle clearance until reaching minimum instrument altitude (MIA) or minimum en route altitude (MEA). Pilot compliance with an approved FAA procedure or an ATC instruction transfers that responsibility to the FAA; therefore, do not assign (or imply) specific course guidance that will (or could) be in effect below the MIA or MEA.
EXAMPLE-
“November Eight Seven Six, are you able to provide your own terrain and obstruction clearance between your present altitude and six thousand feet?”
2. If the pilot is able to maintain terrain and obstruction separation, issue the appropriate clearance as prescribed in para 4-2-1, Clearance Items, and para 4-5-6, Minimum En Route Altitudes.
3. If unable to maintain terrain and obstruction separation, instruct the pilot to maintain VFR and to state intentions.
4. If appropriate, apply the provisions of para 10-2-7, VFR Aircraft In Weather Difficulty, or para 10-2-9, Radar Assistance Techniques, as necessary.