Had this exchange with someone I've seen once before:
'Would you be able to see me tonight sometime'
'Sure, let me know a time'
'Would. 9 be ok'
'Yes, would you like me to book that for you?'
'What is your address'
'I'm based in x, have I seen you before at this address? Let me know if 9pm is certain for you'
'Ok I have been before'
'So is that yes or no for 9pm?'
'Can I let u know in an hour xx'
He's been doing this for months and it's never materialised into a booking. I finally snapped and told him that he need only get in touch with me once he is certain of a time as it's pointless texting back and forth unless he knows if he can commit or not. Thankfully he responded saying he totally understood. Predictably said he couldn't make 9pm though
I think a lot of these guys just don't realise how annoying they are.