Felt my ears burning...
I rather think it depends on (a) what brand and type of tea you are drinking and (b) how strong you have it.
If you are like me, and simply wave the tea bag in the direction of the cup as you walk by,
it's not going to have anything much of anything.
And it's possible that the brands vary. After all, the only specific one mentioned by Allan Borushek is Instant Dandelion, and it only has 0.5g per cup.
I checked with Fitday, and they say a 250 mL cup of herbal tea only has 0.474 carbs.
So basically I'd be looking at the big picture. Are you still losing weight? Because that's the bottom line. For now, I'd continue to enjoy the tea, particularly if you drink it fairly weak, and only worry if you find your loss seems to be reeeeeally slow. Mind you, I've never heard of anyone stalling because of herbal tea.
Of course if the tea tastes sweet....but then you wouldn't be drinking it, would you?
The other thing to remember is even if your carb count was bumped up a little (and I seriously doubt it will be) there are many, many people losing really well on plans where the carb count varies from 30 to 60g.
Cheers, guys, hope that helps a little.
Roz