I got this NOTAM today:
!IDA 12/049 IDA SVC GROUND COM OUTLET COMMISSIONED KEY FREQ 121.7 2 TIMES FUEL DELIVERY /4 TIMES SLC ARTCC /6 TIMES BOI AFSS /8 TIMES 911DISPATCH SVC WHEN TWR CLSD 1412101345-PERM
This looks like a good thing: the ability to make various calls (including 911) on the ground control frequency when the tower is closed. Since KIDA tower closes very early it is especially useful (the fueler stays open after the tower is closed). And 911 (emergency services) dispatch might come in handy, considering that there was a New Year's Eve murder in Idaho Falls.
Using the ground frequency is much better than using the CTAF, because that would interfere with Pilot Controlled Lighting.
How many airports have or will have this feature?