I've got one of those on my DP(bought my DP used and it came with the machine); but it doesn't always pull the key out of the chuck....may have to do with the geometry of where it is mounted. Maybe I need to fool with it a bit?? My previous DP had a "safety key".....had a little spring loaded tip that forcibly expelled the key from the chuck if there was no pressure on it. I hated that key with a passion and almost modified it to work like a "normal" key; but never did.
Not normally, but I do pull the safety key out of the switch. My key also has the self eject pin. A real pain at times, but I have never considered modifying it.