True. Coupons are like sales. You haven't realized any taxable income.

Frequent flyer miles are a bit different. Everyone knows that they have some value. The problem is deciding what value and when it is realized. I don't think we have anything to worry about just yet. As the IRS has said:

"There are numerous technical and administrative issues relating to these benefits on which no official guidance has been provided, including issues relating to the timing and valuation of income inclusions..."

They've also said:

"Consistent with prior practice, the IRS will not assert that any taxpayer has
understated his federal tax liability by reason of the receipt or personal use of
frequent flyer miles... This relief does not apply to travel or other promotional benefits that are converted to cash,"

Naturally, these quotes come with the caveat that I'm not affiliated with the IRS and am not providing tax advice to anyone. Long story short, I really like the looks of Virgin's FF program! Simple and generous.