Yes, in general it can indeed be hard to check whether a diploma was issued by a "real" college/university or not. However, there are several simple ways to mitigage this

* As keshlam pointed out, most countries have accreditation organizations (often run by the government). For example, the [Stiftung zur Akkreditierung von Studiengängen in Deutschland](http://www.akkreditierungsrat.de/) in Germany, or the [University Grants Commission](http://www.ugc.ac.in/) in India. If they do not recognize the university, that's a big warning sign.
* Just looking at the website and doing some quick Google searches will probably reveal a lot. For example, the website of Barkley University mentioned does indeed look extremely glossy (almost too glossy for a university), but if you drill down, cracks start to appear. If you look at the page of a specific major, such as the [page for computer science](http://barkleyuniversity.com/majors/computer-sciences/) there's lots or marketing speak, but almost no substance like research topics or teaching details. Also, the faculty members only have master's degrees, and clicking them gives you a 404.

Finally, a diploma is no guarantee for qualification for a specific job anyway, just an indication. If you have a thorough interview with a candidate (possibly with a phone screen first), I doubt someone clueless would manage to slip through.

Also note that it is possible (though difficult) to get a "real" diploma from a "real" university and still not be very qualified. So just listen well during the interview, and as they say, trust but verify.