> For those with less context into social dancing, this is because the typical default "stance" is offset to avoid stepping on each other's feet - each partner's right foot is roughly aligned with their partner's midline.

I presume that is in ballroom.

For Latin, Tango and Swing which are all mentioned: Simply not true. Your hips are so far apart that it doesn't matter.

That being said: you ideally have a key/change pocket in your pants. Or even better, a beltline interior pocket. The latter is where I keep my keys when dancing tango. On the right side btw. You can't tell from the outside.

These pockets are sadly not available in off-the-shelf clothing any more since maybe around the 1940's.

The reason is twofold: you won't feel your keys/change as much and from the outside you wont have anything ruining your leg's silhouette. Left or right. :-P