Whitelists can be very helpful to determine if a file is safe or malicious but no matter how large the whitelists are they can not include every single trusted file. We all should know that malicious files are released into the wild every minute but about 100 times the amount are safe files (new products, updated versions, etc.).
Another thing to consider, most whitelists include many ad-sponsor products, toolbars, scam products, many other products by shady vendors, etc. Think of it this way, security software vendors must advertise their products to in order to sale them or get a large user base, do you really think they want to detect their advertising partners?
Whitelists should never solely be trusted, just because a file is found to be safe or malicious doesn't mean that it really is.
Most open-source products without digital certificates are usually flagged as false positives at the same time you can get the Ask Toolbar which gets the green light from most security software vendors.
Enjoy!!
