Is the Park Service Billion-Phobic?

Last week's furor over the geologic age of the Grand Canyon and what park rangers supposedly can and can't say, along with putting trillions of electrons to work in the blogosphere and wasting quite a bit of time for an awful lot of people, also revealed that the National Park Service seems to be billion-phobic.
Yep, the agency struggles with the "b" word. At least when it comes to Grand Canyon National Park's web pages addressing the age of that big hole in the ground.
Skip over to the site's page of frequently asked questions and you'll see the following answer to the question of "How Old is the Canyon":

That's a tricky question. Although rocks exposed in the walls of the canyon are geologically quite old, the canyon itself is a fairly young feature. The oldest rocks at the canyon bottom are close to 2000 million years old. The canyon itself -- an erosional feature -- has formed only in the past five or six million years. Geologically speaking, Grand Canyon is very young.

And in addressing the ages of the rocks exposed in the canyon the park says this:

Although the oldest rocks at Grand Canyon (2000 million years old) are fairly old by any standard, the oldest rocks in the world are closer to 4000 million years old.

2000 million? 4000 million? Whatever happened to 2 billion and 4 billion?

I was so piqued by the missing "b" word that I contacted the folks at the Grand Canyon. The answer, according to park spokeswoman Maureen Oltrogge, is that most visitors are more comfortable dealing with millions of years, even if it's thousands of million, than with the concept of a billion years.
"A lot of the staff giving (interpretive) programs finds visitors have problems jumping from millions to billions," she told me. "These people deal with providing programs every day. This is the decision that they made to communicate with visitors."
Now, that answer might not sit well with everyone, myself included, as I'm much more comfortable in describing the geologic age of the Grand Canyon as around 2 billion years rather than 2000 million. And if you closely read the comments to my God, Geology and the Grand Canyon post, you know the park's use of 2000 million when enumerating the canyon's age did rile some viewers, largely conspiracy theorists who figured that the unusual math was intended by the NPS to dance a jig around science when it comes to the age of the canyon.
Millions and billions aside, if you want to see one of the best geologic time-lines for the Grand Canyon, skip over to this page at Chris Clarke's Creek Running North blog.