You can easily configure your system to automatically open all packages with Yank so you can install them with Yank protection. Here's how:
Click once on a package file in the Finder. Any package file will do.
Choose Get Info... from the File menu.
In the info window that appears, look in the Open with: section. Click the popup menu and choose Yank. If Yank does not appear in the popup menu, choose Other... and then locate the Yank application.
Click the Change All button.
Now Yank will launch automatically any time you double click a package file in the Finder.