Does a floater coffee still work without the sugar? Has anyone ever asked for it this way in a bar/restaurant before? I'm guessing they would substitute it with sweetener but I have no idea if the cream still floats or not!
If you make it properly (and they rarely do these days!) you don't need sugar or even alcohol to float cream on top of coffee, I find lots of places use squirts cream nowadays - that has sugar in it. Back in the day when I took my city & guilds in silver service using anything but pouring cream was a complete no no - lots of skills disappearing all the time