Going out with a guy, even out of pity or "I doubt it'll work, but I'll give him a chance" is fine.
Going out knowing you intend never to see him again, but perfectly willing to have him spend his hard-earned money to feed you, in his hope of starting a relationship, is bad.
They're two different things.
You expressly stated a need for there to be an (implicit) promise of a relationship.
Being open-minded, thinking someone might just be nice to know, figuring the evening will be pleasant, etc., is all a far cry from that.
And I really think what you describe is really very rare. Who wants to spend an evening, even with good food, with someone you absolutely never want to see again in your life?