You know what they say about assumptions….
I’m a bit sad reading this thread, particularly the link to the Bicycling article and implication therein. I thought the article was a great and sympathetic portrait of hardworking and hard BIKING day laborers – by taking just the small part where a few guys buy stolen bikes it seems to me that there’s an unfortunate equation being made, and overlooking the main thrust of the article. Which to me is summed up in the article by "What's surprising is how committed these riders are to the activity of cycling--even more, it's hard to admit, than those of us who love the sport."
In the article, and in my experience, the vast majority of bike-riding day laborers, and other lower-income folks, wouldn’t dare put their livelihoods and families at risk by stealing bikes. And pretty much none would have an interest in the kind of bikes the OP describes. Why would someone who puts more miles in a week on a bike than some of us do in a month or even a season, and in the worst conditions (and who have a fierce incentive to not have their only transportation stolen) mess around with carbon fiber and low –spoke-count wheels? Yes, they may want and save for an upgrade from Wally World bikes, but you can bet they’d go for a basic decent mountain bike over anything like the “mismatched” road bikes mentioned here.
We had a rash of high end bikes stolen locally, too. Ones that were locked up and/or garaged, and clearly targeted for their value. Turns out a well-organized theft ring, likely meth related, was broken up because someone not only reported their bike was missing, but had their serial # and gave it to police. So like the others say above, make sure you have that info in a useful place, keep your bikes close, and don’t buy suspicious-sounding stuff off craigslist, ebay, etc…but maybe we can check our assumptions, eh?