I reckon roughly that 50% of the people who enter the bl-osphere claiming to be 13 or 14 are posers. This is just based on watching what happens over time. Most who try to get sexy with older guys are trolling vigilantes or law officers, but not all. The infamous bradnh14 from New Hampshire, a police officer who worked multiple websites as a 14 yo for over 3 years, was well known for trying to hook up with an AF and to get an address to send nude photos of himself through the post. He has recently finally changed his username, which was all over the web in court documents, so you can expect to see him under any number of names now. I don't know if he still uses the 4 childhood photos of himself he used to send around.

BUT, the occasional high-spirited young guy is exactly that, and there's no point offending him gratuitously. Calling someone a poser to their electronic face just isn't nice. I always liken dealing with this problem to the Schrodinger's Cat problem in physics. You have to treat the person as a quantum superposition where they are both real and fake. React to them conversationally as if they were real, and strategically as if they might or might not be real. Until they eventually tip their hand.

As a puzzle, it beats Rubik's cube. However, if you think you can pursue it to find a lil bf, you are headed for big trouble. It is only worth pursuing to give social support to someone who is (or might be) sincerely looking for it.