message: Guests can't send RR
  so they shouldn't try
  lets not hit the HS quite as much
diff: @@ -503,7 +503,9 @@ var TimelinePanel = React.createClass({
  // This happens on user_activity_end which is delayed, and it's
  // very possible have logged out within that timeframe, so check
  // we still have a client.
  - if (!MatrixClientPeg.get()) return;
  + const cli = MatrixClientPeg.get();
  + // if no client or client is guest don't send RR (vector-im/riot-web#3758)
  + if (!cli || cli.isGuest()) return;
  var currentReadUpToEventId = this._getCurrentReadReceipt(true);
  var currentReadUpToEventIndex = this._indexForEventId(currentReadUpToEventId);
  