A standard rebuttal to OCing being foolish/dangerous that has stood the test of time rather well:
Show me one verifiable (w/cite) instance where a normal citizen OCing has ever been subjected to a gun snatch anywhere in these United States in modern times - LEO, security and active military excluded. Will it happen one day - probably, but when and if it does the numerical ratio will look something like .00001% or less. It didn't happen yesterday or the day before either - were this a common occurrence, we would be reading about it now.
Bad guys may look/see, but they don't like the shift in the odds of probability.
I think we have more to fear from the "good citizens" than the ne'er-do-wells - they would disarm us with false publicity and onerous laws rather than "reaching in."
Bottom line is use retention holster, maintain situational awareness and carry on.
I agree completely Grapeshot.
There are some things that you can do to minimize gungrabbing.
The further back you wear it the more accessible it is to someone else.
Some sort of retaining strap or other device makes it harder to grab.
I don't do it anymore because it looks cowboyish...but cross draw puts the grip out of normal reach for grabbing from the rear.
And last, learn how to retain it in a scuffle.