Where are you located? Aren't all your bags screened?

All of our bags are screened now, sending bags without a passenger is fine, because they have been cleared with the TSA. That directive came out a long time ago.

I was under the impression that all bags in the USA are screened now.

You would have to ask your company if you would be held liable. You might not be held liable, however, making a costly/security issue FAA mistake could land you unemployed.