Haven't done any direct comparisons, myself. Haven't typically lived in spots where smash-and-grab type thefts occur much. Once, had a seatpost+seat removed from a bike where I still (stupidly) had the quick-release lever on the seat tube collar. My own bikes tend to be clean and well-maintained, though looking relatively low-cost as compared to many bikes today. (A bit "under the radar," you might say, in the hope it'll matter a damn.)
No idea whether any clear difference exists. But it's easy enough to see that a thief that's looking for something good will tend to gloss over the nearly valueless bikes sitting nearby. Probably balanced out by the vast number of thieves out there who don't much care what they take, so long as it works.
All a WAG, anyway.