Hello.
There must be at least a dozen discussions on here that detail how to get the logged in user account, rather than the service account, which is what's happening with your script. Any policy, Extension Attribute or other stuff from Casper Suite runs as the service account the Mac is set up for, rather than the user that's logged in.
Here is a search I just did that pulled up most of the discussions on this. I think it would be better to look through these than to re-post the information to another discussion:
https://jamfnation.jamfsoftware.com/searchDiscussions.html?query=get+logged+in+user&submit=
Have you considered moving that plug-in to the main /Library/Internet Plug-Ins folder instead, and then inventorying that? If you inventory against something in a home directory on a multi-user system, it won't account for different versions in different home folders.
This workaround resolved the issue. Thank you.
Incredible, the genius Dev team at WebEx prompt you to "Install for all users?" and you enter your credentials, and it gets installed in your home directory...
bash-3.2# defaults read /Users/username/Library/Internet Plug-Ins/WebEx64.plugin/Contents/Info.plist
{
BuildMachineOSBuild = 11E53;
CFBundleDevelopmentRegion = English;
CFBundleExecutable = WebEx64;
CFBundleIdentifier = "com.cisco_webex.plugin.gpc64";
CFBundleInfoDictionaryVersion = "6.0";
CFBundlePackageType = BRPL;
CFBundleShortVersionString = "1.0";
CFBundleSignature = WEBEX;
CFBundleVersion = "1.0.0.205";
CSResourcesFileMapped = 1;
DTCompiler = "com.apple.compilers.llvmgcc42";
DTPlatformBuild = 4E3002;
DTPlatformVersion = GM;
DTSDKBuild = 10K549;
DTSDKName = "macosx10.6";
DTXcode = 0433;
DTXcodeBuild = 4E3002;
WebPluginDescription = "WebEx64 General Plugin Container Version 205";
WebPluginMIMETypes = {
"application/webx-gpc-plugin64" = {
WebPluginTypeDescription = gpc;
};
};
WebPluginName = "WebEx64 General Plugin Container";
}
bash-3.2#
bash-3.2# ls -l /Library/Internet Plug-Ins | grep WebEx
bash-3.2#
I guess the Dev team at WebEx is next on our public lambasting list...

OK, repackaging to put in the right place. #sigh