ICE was the entity acting lawlessly, and tht were sent to support it.
>then they left without incident
They did not “leave withot incident”. Except in the sense that no additional incident was caused by their departure.
But, yes, the LA deployment was both a test and a warning sign (and, like the DC one, also a deliberate distraction from other things the Administration wanted to take a less prominent place in the national discussion at the time.)