Perhaps I'm not the best person to answer this question as I have very low tolerance for tardiness; however, I do realize that sometimes lateness can't be helped. I say if it's a first date and the person has shown a sense of responsibility in all other aspects, give 'em a good 30 minutes. If it's past that and you haven't received any communicable updates, this is just rude behavior and should not be rewarded by your willingness to partake in it. Your time is just as valuable for gods-sakes!
Maybe I'm bitter because this actually happened on my first date with my ex-husband. After 30 minutes of sitting alone at a dinner table while all the servers stared at me, I decided it was time to leave. I should have read the signs then, when he called and was shocked and actually acted insulted that I would leave before gracing me with his uber-important presence. As if I had nothing better to do than sit there alone in a restaurant because he was tied up at work and didn't manage his time well enough to get to our date promptly!
Obviously we rescheduled the date, but I have often thought about how this rudeness was a big warning sign of things to come in our relationship. He was chronically late throughout our entire courtship and marriage no matter how much I professed that it was a nonverbal message to me that shouted, "My time is more important than yours!!!" He even showed up 20 minutes late to our "last ditch" marriage counseling appointment with the therapist reminding him of how a partner can glean information from such behavior. Alas, it never seemed to get through.
So again, there are the exceptions and flexibility always needs to be adhered to when navigating the, sometimes intimidating, dating scene, but I remind you to stay alert and look for other cues from potential mates. It's often said that actions speak louder than words and to this, I couldn't agree more. We live in a pressure filled world these days, but if you would like to be in a respectful and equitable relationship, punctuality and consideration of your time plays a very important role in that. At least in my oh-so, and ON TIME, humble opinion!