Imagine if this were to become common habit for a lot of guests. It would be madness around the pool. I guess the number and positioning of chairs complies with security requirements.
I would not rely on that. Chat CM's are notorious for giving out incorrect information. I was at the WL main pool and some guests had their own chairs and were told by the lifeguard they (the chairs) could not be in the pool area. You might be able to get away with it in a quiet pool, but not a main pool, especially if it's so crowded as there are no chairs available.