I was accompanying a friend who had to serve the country, it was 2 months ago, and I had the chance to see how the Thais recruit soldiers for the National Service. Not talking about the under-the-table stuff, but generally, it's held in public areas, such as temples, and municipal parks. So you see, the place is very crowded, parents and guardians who were praying for their sons to be able to 'skip' the recruitment as Thailand is having a problem from both the Southern Terrorism and the Cambodia's Prime Minister's foul mouth in an attempt to invade the Thai's territory. It was a long process, from various of attentions such as, whether the man is a 'shemale' or whether you have any defects or various.. What you're seeing is actually in temple, not in any cage or prisons, even though the angle may made it look otherwise.. Cheers.