Piston priority is random

When more than one piston is activated at the same time, the priority is random. This means that, if one piston blocks another when extended, then which piston will be extended is completely random. To recreate, just place 2 or more pistons so that when they are extended, their heads are in the same block. Now, make a redstone clock (or turn them on manually with a lever), and connect all the pistons with the same redstone wire. You will see that the piston that will be activated is random: it will change without following no paterns. The expected result would be that the same piston is allways extended (probably the one closer to the redstone source, and if they are at the same distance, then depending on the coordinates or the orientation. Overall, whatever consistant activation is expected).

Apparently, this also causes randomness in other piston redstone circuits, which will sometimes work or not randomly under the same conditions (classic observer flying machines are a good example, image below [gotten from a youtube thumbnail by “CowCupz”], both pistons are sticky pistions).