As a social service (dating) developer i encounter bots and scammer problems more and more, especially in recent years. My team is also considering all kinds of kyc-ish approaches, services that detect vpns, prevention of anonymous emails, etc. I don't like it one bit. But what do you think should one do? A awrvice can become unusable real fast if nothing is done to curate the users...? 

 Impose an economic cost, either via payment or proof of work.