In my University we had a research team that did a comparison between Wikipedia and Encyclopedia Britannica. We compared up to 20 different Wiki pages all of various fields by sending them to professors that specialized to those fields. Out of the 20 that were reviewed by the professors, the Encyclopedia Britannica had 3 errors, and Wikipedia had 4. You can say the probability of Wikipedia being incorrect is a bit higher, but not entirely wrong.
I trust Wiki, but I made a habit to check, double check and triple check the sources cited at the bottom of the Wiki page before accepting it to be true whenever I need information for a paper.
Oh Joe, that is a funny story by the way .. haha