As nearly everyone has a mobile phone today, one actually expects the other to have one. I think that not possessing a mobile phone has already become a stigma. If you do not have one, you require others to adjust their behavior – e.g. they need to be on time, they can not reach you while you are on the go, etc. It's kind of like you were disabled – others have to cater to your limitations. However, unlike someone who is physically challenged, you choose your disability freely.
I wonder how long it will take until we expect others to have a navigation system with them. Today, while walking to the university, a car driver asked me for directions. Unfotunately I could not help him. And a small part of my brain said "Bad luck. It's his own fault if he has no GPS in his car."
Disclaimer: I have a mobile phone. I have no problem if someone does not have one. It was only a small part of my brain that thought this negatively. I do not generalize my observations – it just feels as I have described.