Perhaps it wasn't clearly articulated, but I see some moral dilemmas here.
1) Competing goods: obeying the law (civic virtue; collectivism) vs. personal happiness (hedonism; individualism).
2) Competing concepts of civic virtue regarding laws that won't be enforced: Is it better to (a) vigorously oppose such systems, because e.g. they lay the groundwork for tyranny, or (b) accept that some enforcement sloppiness is beneficial for various reasons, and should therefore be accepted?
On the one hand, you could argue that taking advantage of the IRS deciding not to bother with air miles is wrong.
On the other hand, if you decided to include air miles as taxable on your return, you might be obeying the letter of the law.
This reminds me of the central plot point of The Good Place, which I won’t spoil here, but will paraphrase indirectly: “at what point (if any) is it acceptable to stop considering the second- and higher-order consequences of our actions or inactions?”
I tend to hew toward your 2(b). If even the IRS isn’t going to bother, why would I if it won’t meaningfully matter?
