Do you think that the carp needs to have the rig in its mouth and not know it's picked up a rig in order to catch? I think that once in its mouth, as long as the mechanics of the rig are sound even if it tries to eject immediately it stands a good chance of getting pricked and then bolting resulting in a run. For instance I think the effectiveness of the chod rig, especially a medium to long choddy, relies on the spring in the bent hook length. The carp sucks which straightens the hook length by pulling the bait end against the resistance of the line it is attached to. Then the elastic properties of the mono spring the hook downwards into the bottom lip once the carp stops its sucking motion. I also believe a similar thing happens due to gravity and buoyancy with other rigs, especially so with a large hook and varied buoyancy baits. I fish rigs with the idea that once a carp decides to take in the hook bait, once it's done so the hook should be contacting flesh almost immediately upon the carp stopping sucking, not relying on the carp to move off to get that initial hook to lip contact. Big sharp hook and away we go! This is IMHO though, and I'd love to see video footage of 20 odd pickups side by side of a large snowman with a size 2 hook vs a 10mm wafter with a size 10 hook.