First off, you're getting a good sense of the kind of employer this guy might be. Obviously, your convenience is not the issue to them. These are already warning signs, and you haven't even met the guy in person.
This whole starbucks thing is a trip. I can't believe this guy doesn't understand why you might want to meet on neutral ground.
At this point, I'd just send him an email and say "I'd be much more comfortable meeting you at your office during a lunch break next week." or "I'm sorry, a family function has come up for Saturday and I can't make that meeting. I'd like to meet you at your office on Tuesday @ 1pm. Please let me know if that's convenient for you."
This whole starbucks thing is a trip. I can't believe this guy doesn't understand why you might want to meet on neutral ground.
At this point, I'd just send him an email and say "I'd be much more comfortable meeting you at your office during a lunch break next week." or "I'm sorry, a family function has come up for Saturday and I can't make that meeting. I'd like to meet you at your office on Tuesday @ 1pm. Please let me know if that's convenient for you."