trend on the screening switch?

[OHBBREF]

I have noticed this more in the last year, especially in the scrimmages I have done thus far and in the W/NBA games I've seen thus far.

A1 is dribbling table side moving opposite top of key, A3 comes out to set a solid legal screen on B1, B3 moves out to jump the dribbler as is the new tendancy, but as A3 cuts away down the lane B1 or B3 uses the body or in some cases the arms to impeed A1's movement toward the goal.

this is rarely being called even in obvious hold ing situations, is there something I'm missing, or am I as the coach said Saturday "the only one who makes that call" ?