A visiting official from a small town PD was visiting a city PD during a riot so he could watch the bigger PD's techniques and learn from them.

The rioting hippies were chanting, screaming, throwing rocks, and flipping over cars. The PD had the fire department blast them with firehoses and that repelled the hippies for a short time, but not for very long. Then CS grenades and OC spray was deployed. That was more effective, but the hippies still came back for more. Finally, the police released their dogs on the mob and they all scattered.

The small town police official turned to a city cop and asked, "Since the dogs are so effective, why not just use them from the beginning?"

"You know how it is with hippies. You gotta bathe 'em and fumigate 'em first or the dogs won't touch 'em."