They're cheap pop up tents that are sold in the millions across the country. You probably know someone who has one in their basement or garage. All the big box stores sell them. And, they're not that uniform, some have cheap blue painting tarps on the side, the silver ones are probably space blankets, and the yellow tents look like the kind catering companies usually have for outdoor events. This is a rag tag camp. Organized money would have RVs and campers there.