Undercover cops in New York are riding the subways with iPods on to entice robbery. Is that a form of entrapment? If not, why not?

Government agents may not originate a criminal design, implant in an innocent person's mind the disposition to commit a criminal act, and then induce commission of the crime so that the Government may prosecute. Sorrells v. United States, 287 U. S. 435, 442. Jacobson was not simply offered the opportunity to order pornography, after which he promptly availed himself of that opportunity. He was the target of 26 months of repeated Government mailings and communications…

The most famous example of Entrapment is probably Jacobson v. United States, a case from the early 1990’s about child porn. In this case, the government repeatedly offered Jacobson illegal content, and provided a whole bunch of reasons why he should purchase it under the guise of free speech, etc.. When he eventually did (after two and a half years of basically being pestered about it), they arrested him.

Not at all.

Why do the Republican city officials at Springfield Ohio continue to deny that immigrants are eating pets to sabotage the Trump campaign, even though immigrant pet-eating is now widely believed to be true?

Enticement is not Entrapment.

Entrapment is fairly specifically defined in law… It happens when the police create a situation where someone commits a crime that they would not otherwise be inclined to commit.

From the circuit court ruling:

When do you start "growing old"?