Oh no! The dreaded totally UNfab booth polo shirt! With regulation black pants and black shoes!
I did this a few months back; sorry no pics. It is what got me to finally get over my phobia about tucking and belting. In my case, the dreaded booth shirt was black-- a black that was so cheap, it didn't even match the required/regulation black pants. It was horrible, I tell you... horrible!!
So.. I wound up tucking that darn shirt. Into slacks very much like yours. Slacks I'd normally NOT belt because of my phobia. And I belted.. with a snake skin belt. And wore with red patent leather round toe pumps -- completely ignoring the dress code. I figured if anyone noticed my shoes (under PPL pants), I'd just say I did not own black shoes anymore. People did notice my shoes, but they liked them, and nobody told me to go home and swap them out.
Second day of the conference, I went even bolder, and tucked the dang ugly shirt into a black pencil skirt, no belt, with strappy snakeskin heels -- throwing all caution to the wind! (Skirts were still within our dress code, as long as the skirt was black). I got a lot of compliments on the snakeskin heels. Only one person mentioned the dress code. I smiled and said, "Oh, I figured that was for men only, since men are apt to wear brown shoes and white socks, if we don't spell it all out for them."