Yeah, this is true. I know of loads of people in the UK on a falconry forum that do it. Once the rabbits are flushed the falcons get them. I'm vegetarian and i think it's very sad when any animal is killed but a person quickly killing them is probably the kindest death for them.
Better than the farmer or whatever poisoning them, or shooting and possibly hitting but not killing the rabbit (then The rabbit goes off and hides And eventually dies from the bullet) better than dying of myxi, or getting eaten by a fox or a wild bird of prey who don't kill them as quickly or painlessly as the falconer does. And they don't go to waste because they feed the falcon and the falconer and her/his family, who then do not need to buy mass produced meat that are raised cruelly. Sad as it is, wild rabbits are on the bottom of the food chain and will be killed at some point By something, usually before they're even 2 years old.