I suspect that if you try to announce after the previous dance, many people still will be unable to visualize who their shadow is. I also dislike the idea that from the mic, we might suggest that unpleasantness could result from the dance. I'm with Ron on this. If the dance is really that wonderful, teach it with the swing while saying what other move people can do if they choose that will have the same result (which will depend on what comes next, but allemande 1.5 covers a lot of scenarios, or DSD 1.5.). And let's think about the scenarios in which people would not wish to swing:
1) it's an ex or some other relationship drama. Um. If you both showed up at the dance, I assume it's because you have decided to be grown up about it. The choices above let you choose how to deal, but I'm not bending over backwards. Anecdotally, I know these two oldsters in my community, he is a bit of a rakish gent and an odd one, she is an old school feminist with a strong personality. They will neither touch nor look at one another, but will position themselves correctly for the next move. If they found themselves shadows, they would grit their teeth and deal.
2) it's a creeper. If this person is that creepy, the leadership need to be dealing with them. It is not the caller who polices creepy behavior. Refusing the swing is legit here. Options above should help.
3) the person is a terrible swinger. Yup. I have had this happen. To this I shrug, say it's just a dance. Swing defensively, or use the alternate. Either way, it's only a few seconds each time, and only one dance, in a lifetime of dances.
I might choose not to call such a dance in a regular hall, but save it for a festival, where most people are good dancers, ex's and enemies have generally already either decided who is not going to attend or screwed themselves up to deal with it.
That leaves creepers. Still a kindness to suggest an alternate, to be used without judgement or hurt feelings if anyone decides they like it better than a swing.
My 2c
Andrea
Sent from my iOnlypretendtomultitask
Maia,
I think it might be better to mention it at the end of the previous dance, so people can choose carefully where they dance without as much chance of offending someone. Clearly explain what a shadow is, and the relative proximity to a dancers position.
Rich