The referenced article did not address leading * - or whatever is possible to generalize a path.
See the orignal post for the problem. Note that I do not know the names of files taht may appear. Also the files that do appear do not have extensions.
Checking with IT my reason for fals positives ws most likely raising the level Heuristics level to Very High to fight a break out. The question still remains as to how to exclude the same low level folder on PCs running various OS and x86 and x64.
Have you tried c:\**\SiteAdvisor\Download\ and selected "Also exclude subdirectories" ?