If someone asked you to go get them some sweetener for their coffee, what would you bring back from the kitchen? You bring back artificial sweetener.*
ETA: Assume that it is your job to get things for people so this question would not be out of the ordinary.
(This is a workplace debate that must be resolved. It is extremely important. Put down whatever you are doing and answer this extremely important question)
So to answer Sabriel's question, the debate started because I was asked to get sweetener for someone's coffee by another PA. I didn't get a chance to talk to the person who asked for the sweetener so I brought back packets of Splenda, Equal and Sweet N Low-the three varieties of artificial sweetener that were in the drawer. The other PA chewed me out because she said I should have brought sugar as well. I said people ask for sugar if they want sugar and "sweetener" does not mean sugar.
Other people heard this and thus, the debate began. Most everyone agreed that when someone asks for "sweetener" they mean artificial sugar and you should bring a selection of those but not sugar. A few disagreed and said you should bring sugar and artificial sweetener.
Well, the person took for fucking ever to make her coffee up but lo and behold, she used the Equal without issue. One of my superiors went and asked her directly about the situation and this was the answer: "I like Equal but I don't ask for it because people don't always have it. If I ask for sweetener and they don't have Equal, I'll get Stevia or Splenda or Sweet N Low or whatever which I'm good with but they'll know not to bring me sugar because I asked for sweetener."
So, debate resolved! Sweetener means artificial sugar!