Police in the US don't have to tell you what they're doing up until the point they decide to exercise their power (i.e. searches or arrests) either, last time I checked. They can ask you to go somewhere and you can voluntarily comply or choose not to.
So you are OK with women police officers dressing up as prostitutes to attract potential costumers and then arresting them on the spot ? That's extremely twisted. There's a reason why in many countries police officers HAVE to wear uniforms.
Yes? I'm pretty okay with this. I'm okay with police going undercover, too, to bust up gangs. It turns out that policework is more than just standing in a pretty uniform.
There are two points I want to address here: first, let's be clear that if you commit a crime just because somebody asks you to, it's probably better if the police have you on their radar.
Second: Let's not forget what you were originally complaining about. "The fact that they were setting a trap for him" is what you said.
But it's not really the same sort of trap, is it? In one scenario, you think the police are tricking somebody into committing a crime, so they can be arrested. Sure, that's a valid and interesting discussion to have. But in the other scenario, you're complaining that somebody who has ALREADY committed a crime, and confessed to it on the phone, with no duress, is being tricked into being arrested. That's a very different situation, and I'd be very interested to know why you think that this situation in particular is objectionable. The kid committed a crime; he confessed to it freely. The police got busy catching him; isn't that exactly what you think they should be doing? He's not an innocent person being tricked into a criminal act.
