Does not apply when doing business with the Government.
Seriously, how is this even remotely legal? The government pays retention or re-enlistment bonuses to soldiers, who accept them in good faith and carry out their side of the deal, and then comes back many years later and demands the money back?
Any private business that tried to get money back from its employees long after the fact because, in retrospect, it had made payments in error would have to go through the courts, where it would surely be told to bugger off... right?
Yup. The laws don't apply to the institutions charged with upholding them.
Whatsoever, for any cause,
Seeketh to take or give,
Power above or beyond the Laws,
Suffer it not to live!
Additional: Couple more quotes to keep in mind when dealing with governments in any way:
I am altering the deal. Pray I don't alter it any further.
What need we fear who knows it, when none can call our pow'r to accompt?
(No, I'm not going to do the "hot potato" dance. That's for actors. Also, I think there's a different ritual when someone's quoted from the play, as opposed to saying "Macbeth".)
And furthermore: Imagine if you will a future with government-run single-payer health care. An audit of the system reveals that, years ago, you received an expensive treatment without proper approval. Think the bureaucrats who made the mistake will be punished? Ha! No, you'll be expected to pay the money back, with interest. And if it was your late grandmother who received the incorrectly authorized treatment? Despite the longstanding principle that debts are not inherited, expect the government to demand payment from Granny's estate, meaning her heirs, meaning you.
Somebody's gotta pay, and it ain't gonna be one of us! Quick, find some peasant to go after!