I cannot see this shoot out going down the way it did if the LEOs were posturing with a heavily armed, in your face presence. IE: stationed all around the outside of the restaurant in plain sight. Stationed inside the restaurant, even if it meant that they had to order meals.
My jaded instinct is that they wanted/hoped to engage with deadly force and simply needed a legal/just cause to fire on the bikers. Posturing would have/may have defeated that goal.
The very public attack/war by bikers on bikers, contradicts their 1% ethos in every way. See MC 101. http://www.rcvsmc.net/index.html
If a reading of the code is any indication, the Cossacks are likely going to find themselves under extreme duress from here on out. By their sheer appearance, they violated the 1% code in a most egregious way. After reading the code (in their words) it is quite possible that the Bandidos did open up on the Cossacks with gunfire, due to their perceived belligerence, and in doing so, set off the LEO fusillade.
That being said- what are the rules of engagement for the LEOs? Was a command to fire given or required by the teams' commander?
Curiouser and curiouser.