Quite a few professional police officers and criminal justice academics are weighing in on this notion of "pain compliance" in the wake of that pepper spray assault at UC Davis.
As awful as these incidents have been, I can't tell you heartened I am by the fact that people are finally speaking up on this subject. Indiscriminate tasering has been going on for years now, it's clearly documented and rarely has anyone questioned the right of the police to inflict pain for mere non-compliance. (The tasering of the mentally ill is a separate subject.) YouTubes have gone viral and the comments to them suggest that many, many people find such violence hilarious and support it fully. I won't even go into the way Hollywood uses it for cheap laughs.
Indeed, the most common arguments I hear on this topic is "if an officer tells you to do something, you don't ask questions, you do it" and "the cops first obligation is to protect his own safety and the safety of other cops." This means that a police officer essentially has the right to immediately taser/pepper spray anyone who doesn't immediately respond in order to preserve his or her own safety. And the definition of "safety" is pretty malleable, as we saw this week-end: