First TATL in a while, and the confirmation email has a strange box stating: "If you do not check your bags through to your final destination you may incure [sic] additional charges"

Is this new? I've never seen it before and google doesn't turn up anything. Is this a way of cracking down on ex-EU journeys? Or, is this a US-only thing? That would explain the reports in previous short-checking threads about outstations unwilling to short check bags.