In their Terms and Conditions they all have something like this.
"From time to time, while You use Our Services, You may interact with automated online accounts and/or false profiles, which all its content has been generated by either: a) real persons that have been only contracted or employed by Us for the purposes set-forth below; or/and b) by automated programs or scripts, which dialogues none really exist and have been generated exclusively by programming (Hereinafter, collectively referred to as Automated Profiles).
The purpose of the implementation of Automated Profiles in Our Site is to enhance Your amusement experience and providing You with entertaining and conversational services, so You can be stimulated to use Our Services more extensively, for example, help You to intercommunicate better with other Users which are actually real.
Please, note that any of the interactions made by Automated Profiles are the result of, in any manner, a natural person’s profile. These communications and contents may seem authentic, however, they shall be considered as false.