Students DO hear this all the time, and at this point, everyone else in the world has, too. As a teacher, I understand why, but I also understand that this dictum is utterly misguided. Wikipedia is no more untrustworthy than the average college textbook–and unlike a textbook, Wikipedia can be corrected instantly, where the textbook has to produce a separate list of corrections. Sure, you can go in and screw with Wikipedia, but it’s actually very good at detecting that sort of thing and will either reject the change or flag it for human intervention.
The problem isn’t that people can mess with Wikipedia, it’s that we don’t TEACH Wikipedia–we just state over and over that it’s “not trustworthy” until people everywhere believe it. Why? Because it’s been drilled into our heads, too. And because it’s easier.
A 2017 Edelman survey found that 64 percent of respondents trusted search engines for news and information, a slight increase from the 61 percent who did in 2012, and notably more than the 57 percent who trusted traditional media. (Another 2012 survey, from Pew Research Center, found that 66 percent of people believed search engines were “fair and unbiased,” almost the same proportion that did in 2005.) Researcher danah boyd has suggested that media literacy training conflated doing independent research with using search engines. Instead of learning to evaluate sources, “[students] heard that Google was trustworthy and Wikipedia was not.”