It is really amazing how many bogus files exist in Kazaa. I have tried twice to download Matrix Revolutions, and both times the videos were totally different than what they were supposed to be (the first was "Minority Report", and the second was a movie I had never heard of before and I cannot recall anyway). In the past I have bumped into similar occasions of D/Ling a movie and getting a porn film instead. I have nothing against porn films, but frankly, when I want one, then I can simply D/L it myself, and so I should not be tricked by geting one when I think I get something else! B)
Since videos are measured in hundreds of megabytes, getting a wrong file is quite frustrating after a very long time that you have waited for its D/L. I know that there exists the K-Sig utilty that could help here, but unfortunately one has to be lucky enough to find the hash shared in a reasonable speed (something not always common). The only other solution I have found as far is to preview the video when it has started D/Ling, and kill it in case it is not what it was supposed to be.
I don't know if this problem exists because people mistakenly name their files (in which case I would ask them to be more careful), or because they like to play nasty games with rest of us (in which case I prefer not to comment)...
Anyhow, I guess that if we wanted everything to be perfect we would simply go and buy the video (or music, or software, or...). We like it that way, even if we have to pay a small price!