Both the pre TSA document checker contractors and the TSA personell just eyeball the boarding pass. They do not cross reference any PNR or printed list of passengers. So to the couple of you worried about gettinc caught, can you just give us a hypothetical of how a pax who alters the date on a boarding pass might get caught if they never try to use the document to actually board a plane or change a flight reservation? The use of the bp would solely and exclusively be to access the gate area and nothing else.

And if (through some extraordinary event) the pax got caught, couldn't a shreud and good defense attorney get them off? Would charges even be brought?

The only way I see someone getting caught is say if something happened, and the authorities sealed off the terminal. But usually if something happens they just evacuate the terminal, and then re-screen all the pax, so this method of getting caught may actually not even be valid. In other words, I can't think of a time when a terminal was sealed off, and when boarding passes were checked against passenger lists before pax were allowed to leave the secure area.

This may get down to someones risk profile more than actually due to being plausible that one would get caught.