I've removed mine. Sometimes within minutes of getting a new bike home, sometimes after a few years and the thing is loose. Having said that, just last weekend, for the first time ever, I threw a chain between the spokes and large cog on my MTB. Still not sure what happened, may have back pedaled at the wrong moment in an awkward situation.
Damn that chain was jammed in there. It took several minutes to get it out and I had some doubts I could even do it. Bike wouldn't roll, so I had thoughts of carrying the bike several miles. Not sure what the dork disk would have done differently. Maybe the chain wouldn't have come off at all, maybe the disk would have just been something else jammed in there making it even harder to pull the chain free, or maybe everything jammed up, but the disk would have made it easier to pull the chain out. I'll never know.