No offence, Bert -- I insult only humans! Multiple addressees
  sentence-level attack on toxicity detection neural network
Sergey Berezin Reza Farahbakhsh Noel Crespi
We introduce a simple yet efficient sentence-level attack on black-box
toxicity detector models. By adding several positive words or sentences to the
end of a hateful message, we are able to change the prediction of a neural
network and pass the toxicity detection system check. This approach is shown to
be working on seven languages from three different language families. We also
describe the defence mechanism against the aforementioned attack and discuss
its limitations.