Airlines are notorious for this. One-day return? Business traveller! Hit him! Searching flights on a Saturday afternoon? Private travel – let's discount. High-D

Airlines are notorious for this. One-day return? Business traveller! Hit him! Searching flights on a Saturday afternoon? Private travel – let's discount. High-DPI display? Did someone say "discount"? I meant "this counts" – as a good reason to raise your prices.