I am well aware of the distinction between eceilidh and "social dance" but, outside of the historic dance repertoire, there are very few dances that require a set tune even if some have one commonly associated with them.

If you are actually teaching then unecessarily linking dances to specific melodies can make life more difficult for the dancers if they subsequently encounter the same dance with a different tune or, worse, that tune used for a different dance. I know that SWMBO will curse bitterly and make mistakes if the band uses a tune that she has had associated with a different dance.