diff --git a/web/app/assets/javascripts/alert.js b/web/app/assets/javascripts/alert.js
index 077240d4e..7ba13363c 100644
--- a/web/app/assets/javascripts/alert.js
+++ b/web/app/assets/javascripts/alert.js
@@ -10,7 +10,9 @@
         function events() {
             $('#btn-alert-ok').unbind("click");
             $('#btn-alert-ok').click(function(evt) {
-                callback(sessionId);
+                if (callback) {
+                    callback(sessionId);
+                }
             });
 
             $('#btn-alert-cancel').unbind("click");
diff --git a/web/app/assets/javascripts/sessionList.js b/web/app/assets/javascripts/sessionList.js
index 131c987aa..49af23e00 100644
--- a/web/app/assets/javascripts/sessionList.js
+++ b/web/app/assets/javascripts/sessionList.js
@@ -137,19 +137,69 @@
                 // wire up the Join Link to the T&Cs dialog
                 var $parentRow = $('tr[id=' + session.id + ']', tbGroup);
 
-                if (session.approval_required) {
-                    $('#join-link', $parentRow).click(function(evt) {
-                        openAlert(session.id);
-                    });
-                }
-                else {
-                    $('#join-link', $parentRow).click(function(evt) {
-                        openTerms(session.id);
-                    });
-                }
+                $('#join-link', $parentRow).click(function(evt) {
+                    joinClick(session.id);
+                });
             }
         }
 
+        function joinClick(sessionId) {
+            var hasInvitation = false;
+            var session = null;
+            // we need to do a real-time check of the session in case the settings have
+            // changed while the user was sitting on the Find Session screen
+            $.ajax({
+                type: "GET",
+                url: "/api/sessions/" + sessionId,
+                async: false,
+                success: function(response) {
+                    session = response;
+                    if ("invitations" in session) {
+                        var invitation;
+                        // user has invitations for this session
+                        for (var i=0; i < session.invitations.length; i++) {
+                            invitation = session.invitations[i];
+                            // session contains an invitation for this user
+                            if (invitation.receiver_id === context.JK.currentUserId) {
+                                hasInvitation = true;
+                            }
+                        }
+                    }
+
+                    if (session) {
+                        // if user has an invitation, always open terms and allow joining regardless of settings
+                        if (hasInvitation) {
+                            logger.debug("Found invitation for user " + context.JK.currentUserId + ", session " + sessionId);
+                             openTerms(sessionId);
+                        }
+                        else {
+                            if (session.musician_access) {
+                                if (session.approval_required) {
+                                    openAlert(sessionId);
+                                }
+                                else {
+                                    openTerms(sessionId);
+                                }
+                            }
+                        }
+                    }
+                },
+                error: function(xhr, textStatus, errorMessage) {
+                    logger.debug("xhr.status = " + xhr.status);
+                    if (xhr.status === 404) {
+                        sessionNotJoinableAlert();
+                    }
+                    else {
+                        app.notify(
+                            {   title: "Unable to Join Session",
+                                text: "There was an unexpected error while attempting to join the session."
+                            },
+                            { no_cancel: true });
+                    }
+                }
+            });
+        }
+
         function openAlert(sessionId) {
             var alertDialog = new context.JK.AlertDialog(app, "YES", 
                 "You must be approved to join this session. Would you like to send a request to join?",
@@ -159,6 +209,19 @@
             app.layout.showDialog('alert');
         }
 
+        function sessionNotJoinableAlert() {
+            var alertDialog = new context.JK.AlertDialog(app, "OK", 
+                    "This session is over or is no longer public and cannot be joined. Please click Refresh to update the session list.",
+                    null,
+                    function(evt) {
+                        app.layout.closeDialog('alert');
+                    }
+                );
+
+            alertDialog.initialize();
+            app.layout.showDialog('alert');
+        }
+
         function onCreateJoinRequest(sessionId) {
             var joinRequest = {};
             joinRequest.music_session = sessionId;