I am not going to spend in excess, but if a company is paying for me to fly somewhere, I doubt a $30 airport meal is going to break them.
Now there have been times on site with a client, and I had a $120 per diem, where I might eat breakfast and lunch from a vending machine so that I can have a nice dinner, but I would never skip a meal at an airport if I had enough money left for it, and even if I didn't, I'd still charge the company and hope it flies under the radar.
Again $30 isn't going to bankrupt any company that can afford to fly you around.