{
    "checkout.due" : {
        "context_org" : "circ_lib",
        "filter" : {
            "checkin_time" : null,
            "-or" : [
                { "stop_fines" : ["MAXFINES"] },
                { "stop_fines" : null }
            ],
            "-exists" : {
                "select" : {"au" : ["id"]},
                "from"   : "au",
                "where"  : {
                    "-not" : {
                        "profile" : [29]
                     },
                    "id" : { "=" : {"+circ" : "usr"} }
                }
            }
        }
    }
}