I also wonder how the ticket was re-instated if it was supposedly cancelled. This had to have been done with a conversation between the passenger and United and with an explanation of the seat being gone.
As for the congresswoman saying she did not receive special treatment: I would think that flying paid economy domestic on a government fare most of the time would not qualify her for GS on revenue. Surely, she is getting GS due to her position which I imagine is common with members of Congress. Since United does not publish their criteria for getting GS status, the process is certainly designed for special entitlements. That may be something the press can look into as well as other stories of people being bumped out of first class for a VIP.