There's no alternate method for locking missiles, but what you are seeing may be players using abilities that break missile locks. There are quite a few of these, which can be used either during the lock process or once the missile is in flight.
Besides d-field, like what, tier 5 EMP field on the scouts? That's the only other one I can think of, besides engine maneuvers, where there is a lot more visual feedback on the screen in addition to the buff in the target info UI.