Jack,

I think that the music and dances themselves are well planned in these circumstances... i.e. on the SCD scene.

While I'm sure they'll pay attention to what the dancers are doing, I'd imagine that they'd be a little less flexible than ordinary ceilidh bands.

The dances will last for a set time(as will the tunes)and the dancers will usually be expected to know what they are doing too.
Unlike your average SMG hoolie   :-)

I'd imagine that the music is more of a "plan" for the programme as opposed to the musicians actually needing to read the dots as such.