It’s actually really simple: did they message me first? 100% of the time they were bots.
The problem is, anyone you message is using the same test, thus deciding that you are a bot. The only logical way to handle this is to ensure you start all messages with “Greetings fellow human, I have perused the photographs of yourself that you put online. Not only are they very attractive – they’re interesting too. You did the right thing putting them up, and it was very brave to do so. I would lime to get to know you better…” That way no-one will be confused.
The problem is, anyone you message is using the same test, thus deciding that you are a bot. The only logical way to handle this is to ensure you start all messages with “Greetings fellow human, I have perused the photographs of yourself that you put online. Not only are they very attractive – they’re interesting too. You did the right thing putting them up, and it was very brave to do so. I would lime to get to know you better…” That way no-one will be confused.