There is a patern of behavior to these things also. If you have been using P2P long enough you find the same length files are always and I repeat always nasties. For example: There is a file that appears with many differant name's that is 106. something kilobits long and another that is 885.something kbs. these appear most often with multimedia files such as movies.
I have even found that there appear to be networks that specialize in custom files. I mean that sometimes when i have tried to find a file and have difficulty doing so often times one of these nasties will appear with the exact file name i asked for.
The rule of thumb I found is to always and I reapeat always look at the size of the file and se if it is kbs or mega. That will give you a clue as to if you are downloading your desired file or a pig in the polk.....