> in most cases, I would expect an offer to be contingent on references
You work in tech in the Bay Area and this is your expectation? It's certainly not mine - I don't expect them to call anyone at my current employer and would be annoyed if they did.
I absolutely do not – I work in tech in the UK. That's why I added the proviso that expectations might vary regionally.
However, if I were to explicitly provide a contact at my current employer as a reference (which seems to be broadly standard practice in this country) then I'd expect them to be contacted.
You work in tech in the Bay Area and this is your expectation? It's certainly not mine - I don't expect them to call anyone at my current employer and would be annoyed if they did.