Mac OS X is asking whether you want to open a file which came from the Internet. With 9.8pr2 we have added a function to get this information from a file. You can also set the information and clear it.
Check the new Folderitem.MacQuarantinePropertiesMBS as MacQuarantinePropertiesMBS method and the MacQuarantinePropertiesMBS class.
Some links: MacQuarantinePropertiesMBS class documentation Prerelease Downloads New functions in 9.8