Good point. I should have taken that into account. It is not as perfect as hanging out with a friend. Your date will probably lack experience with the activity and might wind up feeling bored or uncomfortable. Also the emotional stress from the sexual tension, your unfamiliarity with each other and the uncertainty of your relationship all have their toll on your enjoyment. On the other hand, it is not as simple as time and money being flushed down the drain once you break up.
The activity doesn't need to be a sport or something you get skilled at. I like to take walks to a park near my house, so when I went out there with a girl it was fun for me, we had good conversations, and nothing was "flushed down the drain" as you say, even though I never saw her again.
The last thread didn't fare too badly, I think; let's make it a monthly tradition. (Me, I'm more interested in thinking about real-world policies or philosophies, actual and possible, rather than AI design or physics, and I suspect that many fine, non-mind-killed folks reading LW also are - but might be ashamed to admit it!)
Quoth OrphanWilde:
Let's try to stick to those rules - and maybe make some more if sorely needed.
Oh, and I think that the "Personal is Political" stuff like gender relations, etc also belongs here.