Neither is upholding and defending the constitution yet we accept this as a basic oath of office. I can see technical arguments either way; however, ...
> Until then LAPD, LASD, CHP, etc. are expensive enough
We are, on the most basic level, really just talking about a phone call or a copy of a report being forwarded to DHS/INS. This does not seem resource intensive and it can be seen as obstructive to refuse to do this; particularly, if they had this reporting arrangement previously.
> We do? e.g. AB 60 driver's licenses
No one is _required_ to get one of those and there is no penalty for being without one. So the city has a large population of people who are not known. To take the argument to the extreme, this implicates disaster and evacuation planning, as well as resource management within the city. It tends to show their main function is obstruction and not service.
A more moderate policy might be, if you have an AB60 license, you receive sanctuary protection, but if you do not, then you may not, and may have your details forwarded to federal immigration. I would argue this is the most equitable for everyone, both immigrants, and citizens.