Yes, I am fresh off the phone with a supervisor at US who disclaimed any knowledge of the security-fee holiday. She tells me that I will not get my $5 back.

I won't go to great lengths over $5, but I did promise to email her an article explaining the holiday, so if anyone has anything I can send, please post or email privately.

Interestingly, my sister used her own UA miles for an award ticket on the same flights. I wonder if she would have better luck contacting UA for her refund.