when starting chat from memberinfo, allow guest access. in future synapse should make guest_access a default for the private_chat preset.

src/components/structures/MatrixChat.js

@@ -467,6 +467,7 @@ module.exports = React.createClass({
                 var Loader = sdk.getComponent("elements.Spinner");
                 var modal = Modal.createDialog(Loader);
 
+                // XXX: FIXME: deduplicate this with MemberInfo's 'start chat' impl
                 MatrixClientPeg.get().createRoom({
                     preset: "private_chat",
                     // Allow guests by default since the room is private and they'd

src/components/views/rooms/MemberInfo.js

@@ -248,8 +248,21 @@ module.exports = React.createClass({
         else {
             self.setState({ creatingRoom: true });
             MatrixClientPeg.get().createRoom({
+                // XXX: FIXME: deduplicate this with "view_create_room" in MatrixChat
                 invite: [this.props.member.userId],
-                preset: "private_chat"
+                preset: "private_chat",
+                // Allow guests by default since the room is private and they'd
+                // need an invite. This means clicking on a 3pid invite email can
+                // actually drop you right in to a chat.
+                initial_state: [
+                    {
+                        content: {
+                            guest_access: 'can_join'
+                        },
+                        type: 'm.room.guest_access',
+                        state_key: '',
+                    }
+                ],                
             }).done(
                 function(res) {
                     self.setState({ creatingRoom: false });