Using ct_test_message to test logged-in user too

Hello,

we are not using an anti-spam check for logged in users (via Protect logged in Users option) on our website. But we have one form for which we would like to perform an anti-spam check even for logged users. I can use the ct_test_message function when the user submits the form, but I found that it respects the Protect logged in Users option, so it always asses that it is not spam for logged users. Is it possible to override this behavior and force an anti-spam test when calling the ct_test_message (or any other) function? Thank you!