Lots of the folks in our music clubs come from "holiness" church backgrounds (Think Jerry Lou Lewis doing honky tonk gospel), where they have played pianos and lap steel guitars in church services. These will often have guitars, bajos, and mandolines too, occasionall a fiddle too.
   So, pianos and lap steels fit right into "traditional music" in East Tennessee. The younger generations have grown up in these same churches with keyboards and insturmental accompaniment tapes, not pianos; to them, the piano isn't as versatile. I really don't want to have to "police" the keyboards.
    The only reason we would allow electric basses is that upright
doghouse bases are less common that electric basses. You really need some kind of bass.
    Bear in mind that its bluegrass, old time country (pre 1960), old gospel, old-time, early acoustic blues, traditional fiddle tunes.