Since in phx we do not scan boarding passes (ie using bar codes or mag stripes) the only way to confirm that an OLCI boarding pass is legitimate is to either compare it to our computer list of who checked in online or to reprint the boarding pass at the airport. Sadly since people have made fake OLCI passes this is what we do. You may not see us do it, but we do verify all OLCI BPs before the flight departs.

We do have two gates in PHX, A11 and A19, that are testing boarding pass scanners using the bar codes printed on them - at those gates you need to have a bar code on the BP. Also if you're going out of either of these gates and have a BP issued by an "east" station, the bar code on your BP won't work as it's not in the "west" system as such.