Shooting a bareback scene because the actors have negative AIM test results is meaningless, worthless.

1) Any HIV test measures antibodies to HIV developed by the body within X-days of exposure. That amount of time varies by person. It could be 30 days or 300 days.

2) The test does not cover contact after the test date.

The purpose of an HIV test is to inform a medical professional that the patient has been exposed to HIV.

NOT that the person has NOT been... and then can perform bareback.

Medical tests do not determine and declare that someone is "well", only when and if someone is "not well". You can have a temp of 98.6F and still have a bacterial or viral infection.

As with any science, medical tests do not prove that something is "right", only that something (a theory, a formula) is not right/correct.