Crossed and crossed and locked markets can be the result of pent up demand/supply and ambition (and hopefully not an error) They can be great indicators of the short term supply and demand relationship. Imagine a champagne cork being released. Ask why this may be occurring? What just happened? Have things happened very fast? Is price traveling?
They will resolve themselves, if a high demand scenario, the second and third inside markets are usually thin (a few hundred shares on either side) with wider spreads, (greater than 10 cents). With resolution (of the locked or crossed market), a momentary trend is often in place. That in and of itself can ignite a buying spree. A self fulfilling prophecy if you will. It is particularly easy to accelerate a stocks momentum right after releasing the "cork"
The last price is key to watch when a crossed or crossed and locked market corrects itself, if it travels with a little follow through, the above relationship can unfold.
There are also time when the markets simply uncrosses/unlocks and no frenzy follows.
The aforementioned represents my opinions and experience.
I hope this helps.
-Hoyler