We have done recently. (Not TSA - not even US govt...)
And, in spite of our "mid 5 figures" price for the iOS+Android apps for a fairly simple app - the whole program of work the government department included this in, and hence the media reporting of "what the app cost" came to 1.3million dollars.
Now I get people asking me "How on earth did it cost over a million dollars for that app? Surely that's practically fraud!"
If the only requirement is "an arrow that randomly points left or right when you tap the screen" - I suspect _anybody_ who reads HN could whip up a provably-correct solution in under 30 mins just using html and javascript. I _strongly_ suspect there's a +lot_ of other requirements and costs we don't understand here. (But cynically, a lot of those costs could well be high paid consultants writing Powerpoint decks justifying why the only requirement should be "an arrow that randomly points left or right when you tap the screen". That'll be $325k thanks - here's our recommended outsourcing partner who can deliver the app for $11k.)