Even in your own car dropping off your friends or family at a UK airport (at least the London ones) requires paying a £6 fee now. Just to get to the dropoff area, even for 30 seconds as you say.
But hey, at least the luggage carts are free…
At Edinburgh airport, you can park at the Park and Ride nearby but it costs a tenner to get from there to the airport - a distance you could walk in about 20 minutes.
Right, but what do you think the alternative is? There is limited space close to the entrance of the terminal, it has to be rationed somehow. Also what happens in practice is people take advantage. A trust-based 30s wouldn't work. Even with the current fees you can hang around Heathrow drop off and see the police having to move people along, check unatended cars, etc.
In Edinburgh the (small, we often need 2) luggage carts are now £2.