I think that the "ess" should only be added when sexual distinction is being communicated as well. Off the top of my head, I can only think of it coming up for very feminine nouns, such as "temptress" and "mistress." "Waitress" is still doable but discouraged.

You're American then?

Waitress is still very much the term in this part of the world.

I'm american and this is the first I've heard of "waitress" being frowned upon here. My experience draws from Philadelphia, New York, and Silicon Valley (San Fran, Mountain View, and San Jose), but there are so many cultures in America I wouldn't be surprised if some places were moving away from the word.

Yep. See, we were overrun by the PC nuts in the 80s, but there are good parts. In the case of "waitress," I agree with them that the elaboration is unnecessary and pointless. So I value some PC when it delivers precision (but the arguments that certain speech is sexist seems far-fetched; "waitress" is not sexist).

A problem for the PC nuts, in particular those that maintain words like "waitress" are sexist, is that they're very often hastening the descent to a masculine-neutral, and so are ultimately complicit in preserving the very system they oppose.