FWIW: Early on California had a no leftover doses policy. But what do you do when you have more vaccines than eligible people? You lower the eligibility requirements. This probably wasn't official policy but it was required of vaccination site runners to comply with the policy, so as they got towards the end of the day and they still had doses leftover they probably started jabbing anyone who walked in. I don't know what the consequences were from having leftover doses, but they were severe enough that some sites started doing this kind of thing.