It depends on how they bait them. The way Dateline conducts their investigations is in line with how most Law Enforcement Agencies do it.
Entrapment only counts if the person does something they wouldn't normally do, because the Officer/Investigator encouraged them to do it.
If an Officer is undercover and tells you to smoke weed, that's entrapment. If you just smoke weed around an undercover officer, that's not entrapment.
Dateline doesn't go into chat rooms telling people they're a horny 14 yr-old girl looking for penis. They simply act as a normal innocent kid would and wait for predators to bite. That is completely legal.
lol i wonder how many times they do that and the whole time there talking to a 14 year old boy trying to act older to impress the "14 year old girl" lol