The use of "local", Universal Time Coordinated (UTC/Zulu/GMT), or a specific time zone (like Eastern) when specifying the time a message was created or a net is scheduled, or even passing the current time over the net can create confusion for all involved, especially when nets or message traffic cross time zones.
Here, in Carroll County, Georgia, we are close enough to the Central time zone that their and our VHF net times are "one hour off" from each other. Because we deal with the time zone issue on a regular basis, and VHF range is usually limited to less than one hundred miles, it seldom causes a problem.
When it comes to local VHF nets, using local time actually makes more sense. A weekly 8PM net, if UTC were used, would shift back and forth by an hour as we changed in and out of DST. Specifying "Lima", or local time, is usually sufficient. Even better, specifying the time zone (without Standard or Daylight) would make the time clear (8PM Eastern).
As communications span multiple time zones the problem becomes more challenging. For instance, an HF net held in Texas (which has two time zones) could create confusion within the state itself. But, beyond the state borders, the rest of the world would need to know which time zone the net was in, determine the number of time zones away the location is, and then calculate the appropriate local time. Nobody would ever get checked into the net on time!
Like ITU Standard Phonetics, UTC provides a consistent framework to operate within. Utilizing UTC, a single point at which we reference all timed events, makes coordination across time zones much easier. While an operator in Georgia still has to determine how may hours to subtract from UTC (four during DST, five during Standard Time), it's much simpler than trying to determine the number of hours between two time zones and then doing the math! UTC at least minimizes the confusion.
The name for the Prime Meridian, the home of UTC, has changed over the years, often referred to as "Zulu" time, Greenwich Mean Time, International Atomic Time, and finally Universal TIme Coordinated, shortened to UTC. But it's all the same thing, the time at zero degrees Longitude, a line that runs the Royal Observatory in Greenwich, England. From there, a new time zone is born every fifteen degrees of longitude, and an hour change on the clock.
Now for a bit of trivia. When the Architect of Washington, DC, Pierre Charles L'Enfant, began his work he envisioned a new "Prime Meridian" that would be defined by a line that ran from the Capitol to the President's Mansion, which would also become 16th Street. It was called "Washington's Meridian" and was intended to ultimately become the point upon which all time zones would be based. Design changes led to differing locations, with Pennsylvania Avenue traveling Northwest from the Capitol to the White House, but 16th Street still straddles the original Meridian. While the idea of the "Washington Meridian" did gain some traction, there wasn't enough momentum to unseat the British based system the world would formally adopt in 1884.
