> If only one small station is doing it, they might get repercussions. If many stations (or large chains) do it, it might become normalized.

Of course, it won't be presented this way. It'll be presented as 'discounts' (from an inflated base price) for filling up when you're over 50% full, then a lesser discount when over 20% full, etc. And, well, if you didn't bother to take advantage of the discounts then whose fault is that, eh? But it'll be effectively the same.