Agreed. Doing it to mess with the controller is going to get the crew and the airline in hot water.
That said, there is a fair amount of discretion on the Captain's part, and if the pilot was unable to land at Oakland for an unforeseen reason, such as an ILS malfunction at OAK, then declaring a fuel emergency sooner may be justified.
Knowing that fatigue may also be a factor, which could also result in a missed approach, and they are required to have sufficient fuel for several ILS approaches before diverting, without using their final reserves, could push them to declare a fuel emergency.
Typically, the Captain would say something along the lines of "I can only hold another 10 minutes, before declaring fuel emergency", prompting ATC to get them sequenced for approach promptly.
That said, there is a fair amount of discretion on the Captain's part, and if the pilot was unable to land at Oakland for an unforeseen reason, such as an ILS malfunction at OAK, then declaring a fuel emergency sooner may be justified.
Knowing that fatigue may also be a factor, which could also result in a missed approach, and they are required to have sufficient fuel for several ILS approaches before diverting, without using their final reserves, could push them to declare a fuel emergency.
Typically, the Captain would say something along the lines of "I can only hold another 10 minutes, before declaring fuel emergency", prompting ATC to get them sequenced for approach promptly.