(((seesaw))),

You actually handled the encounter well. You did fine with your boundaries and now that you know this person has taken extra steps to meet you, try not to just assume he is going to do something bad. It's probably just an idea he came up with as a way to meet you and talk to you in person and he did meet you in a public place so this is not like he is trying to catch you alone. You now know this guy has an interest in you, the ball is still in your court and you can take charge and make sure you discourage him kindly from further pursuing you and you can also take steps to be more careful about posting your plans on this site where he saw it and made plans to see you.