Re: ...PSA Night...
No, they shouldn't be out casted, Urdu should be promoted among them so that they learn. I see 2 options. 1) Speak English so that it's easier for non-Urdu-Speaking-Pakistanis to understand or 2) Speak mix (if not all Urdu) so that they learn and are prepared for future events.
Personally, I would go with #2. Then from that point on, it should be PSA's job to promote Urdu on Campus (among Pakistani students). Putting burden on them all at once is wrong, I agree, but something should be done about it. They shouldn't just sit there saying oh well, they won't understand. Well, then do something about it.