It might not make sense, but it is never the less the official rule by HiG. Actually, as a house rule, I would even make the inns from River II or B,C&B count, if not playing with I&C. (To be honest, all games I played on table had been with I&C yet.) Why not? The rules are easy enough, don't cause headache with other expansions, everybody is aware, what to do with this tiles. And they are not outbalanced, it there are only one or two of them in the game. ANd yes, I would also play with pig heard.