Code recycling is one thing, but not understanding what that code does when you put it into a production app or not following best practices is another. As Android gains popularity as a platform to develop for, we're going to lose quality as the new folks jumping onto the band wagon don't care how their apps work or look beyond the end goal. This mentality is already popping up with Android Wear developers who cram as much information as they can on the screen and claim that design guidelines are "just recommendations."
The exact same thing happens on every other platform, though perhaps to varying degrees. I refer to it as the Stack Overflow effect. One developer who doesn't know the right way to do something posts a question. Then, a developer who also doesn't know the right way to do it posts how he or she did it. Then ten thousand developers who don't know the right way to do it copy the code without understanding what it does or why it's the wrong way to do it. By the time somebody notices it, signs up for the site, builds up enough reputation points to point out the serious flaw in the code, and actually gets a correction, those developers have moved on, and the bad code is in shipping apps. Those developers, of course, think that they've found the answer, so there's no reason for them to ever revisit the page in question, thus ensuring that the flaw never gets fixed.
Case in point, there's a scary big number of posts from people telling developers how to turn off SSL chain validation so that they can use self-signed certs, and a scary small number of posts reminding developers that they'd better not even think about shipping it without removing that code, and bordering on zero posts explaining how to replace the SSL chain validation with a proper check so that their app will actually be moderately secure with that self-signed cert even if it does ship. The result is that those ten thousand developers end up (statistically) finding the wrong way far more often than the right way.
Of course, it's not entirely fair to blame this problem solely on sites like Stack Overflow for limiting people's ability to comment on other people's answers unless they have a certain amount of reputation (a policy that is, IMO, dangerous as h***), and for treating everybody's upvotes and downvotes equally regardless of the reputation of the voter. A fair amount of blame has to be placed on the companies that create the technology itself. As I told one of my former coworkers, "The advantage of making it easier to write software is that more people write software. The disadvantage of making it easier to write software is that... more people write software." Ease of programming is a two-edged sword, and particularly when you're forced to run other people's software without any sort of actual code review, you'd like it to have been as hard as possible for the developer to write that software, to ensure that only people with a certain level of competence will even make the attempt—sort of a "You must be this tall to ride the ride" bar.
To put it another way, complying with or not complying with design guidelines are the least of app developers' problems. I'd be happy if all the developers just learned not to point the gun at other people's feet and pull the trigger without at least making sure it's not loaded, but for some reason, everybody seems to be hell-bent on removing the safeties that would confuse them in their attempts to do so. Some degree of opaqueness and some lack of documentation have historically been safety checks against complete idiots writing software. Yes, I'm wearing my UNIX curmudgeon hat when I say that, but you have to admit that the easier programming has become, the lower the average quality of code has seemed to be. I know correlation is not causation, but the only plausible alternative is that everyone is trying to make programming easier because the average developer is getting dumber and can't handle the hard stuff, which while possible, is even more cynical than the original assertion and makes me weep for the future.
Either way, there's something really, really wrong at a fundamental level with the way we search for solutions to coding problems. There needs to be an easy way to annotate the fact that a code snippet was derived from a particular forum post, and to automatically receive email notifications (or bug reports) whenever someone flags the snippet on the original forum as being wrong or dangerous. And we as developers need to take the time to learn enough about the OS and the programming environment to ensure that we at least mostly understand what a piece of code does before we ship it in a product.