using the phrase 30,000 years ago and then giving a date of 28,000 BC is unnecessarily clumsy

I agree and don't agree.
If you're talking about times tens of thousands of years ago, two thousand years doesn't make much difference either way. You could use BP or BC.

As regards AD (Anno Domini), there are a lot of conventions in time measurement, and we all have to start the clock somewhere. There is no way you are going to get societies to agree as to when modern civilization started, so you just have to treat the number used for the current year as you do time zones and languages. "When in Rome.."

If I call the current year 2002, it doesn't make me a Christian; nor does it mean I believe Jesus was born 2002 years ago. I'm merely sharing a convention for convenience.


Edit: Arg! Chopped Juan!