Are there any objective rules or guidelines used to determine whether a police officer's conduct was outrageous?
"outrageous conduct" has sometimes been a factor in holding police action invalid under the uS Federal constitution. In particular, there was a line of Supreme Court decisions that would supress confessions if they were obtained by "outrageous conduct". That line of cases became obselete with the Miranda ruling requiring warnings, and also forbidding most of the sorts of things previously lumped under "outrageous conduct". This sense of "outrageous conduct" was a purely court-made concept, not a statutory one, and the standard seemd to have been conduct that was considered shocking or unconscionable by at least 5 Justices.