I need to get from LAX to JFK. The ticket is $ 260 OW. At the same time I see a $149 LAX - PHL ticket with a layover at JFK. So my question is, can I just buy a $149 LAX-JFK-PHL ticket...
Yes.
Yes.
...without violating some Delta rules?
No.
To be sure—will I still get the miles for the LAX – JFK leg?
No, because hidden city tickets is against airline rules.