Mostly, the result I anticipate from "should"ing a norm-violator is that other members of my tribe in the vicinity will be marginally more likely to back me up and enforce the tribal norms I've invoked by "should"ing. That is, it's a political act that exerts social pressure. (Among the tribal members who might be affected by this is the norm-violator themselves.)

Alternative formulas like "you'll get more of what you want if you don't do that!" or "I prefer you not do that!" or "I and others will shame you if you do that!" don't seem to work as well for this purpose.

But of course you're correct that some norm-violators don't respond to that at all, and that some norm-violations (e.g. murder) are sufficiently problematic that we prefer the violator be physically prevented from continuing the violation.