caveat lector*

* "Let the reader beware": What should be the permanently/proeminently visible Wikipedia disclaimer/warning.

Wikipedia is an aggregator of knowledge/information, not a creator of it.

Wikipedia's articles are only as trustable as their references/sources/originators.

Use this notion as a rule of thumb/caveat and Wikipedia can be/is an unbeatable asset...

Wikipedia itself denotes this in article pages where no sources/references are given to support the contents (even if it should be displayed as a clear and permanent disclaimer in all article pages, regardless).

Without verifiability, any information/knowledge is untrustable/untrustworthy/unreliable, by definition.