There's a lot to be said against regulating it away.
Wrapping the entire populace of the European Union in cottonwool, for example.
What's the difference between
advertising a low fare and publishing government/airport charges/fees/taxes on a website
and
offering a trade-in rebate of "Up to €5000" and then having to read through the small print to find that you only qualify for 54c?
Life's complicated. Get used to it