Willy McBoyne I am just back from a singing weekend in Ballyliffin and orange songs were sung amidst others! The Bold Orange heros of Comber springs to mind and I might add NOT sung by a protestant. Though I dont understand why it should be an issue, most (if not ALL) traditional singers dont sing songs (of any description) that might offend other singers in their company. When singers meet, either at a session or singing gathering it's like a family reunion, would you sing something to offend any of your family?
A traditional ballad from either side is acceptable at any session, but not if it is intended to stir up trouble or hurt someone.
Dolly's Brae is a great traditional ballad, The Hills of Carrowdore, The Defence of Crossgar to mention a few that that I have heard sung at sessions, so I don't know where you are coming from.
cheers eoin