It looks like you don't think much of Cairns and that's fine as he definitely has his limitations.I was thinking along the lines that he can fill the 7th/8th spot and could easily fit into a spot when injuries,certain match up's and/or struggles to the defense occur.
7th spot yes, but 8th spot would place him in the minors. I'm ok with Cairns as the #7 in Vancouver, but I'd rather have Slegr in that place. If the Canucks need a part time enforcer, they can get one for extremely cheap. Cairns may be a regular on the Island, but he wouldn't be in Vancouver.