I get a few calls a year from people who would like to save a few dollars on there pool cleaning over the winter time. "Winterizing" is something that's done, usually up north, in very cold climates to help keep things from freezing and cracking. In Southern California we don't have to worry about that, but there are good reasons to NOT drain your pool.
Pool floating or pop out. Your pool is kind of like an upside down boat, and the water in the pool is so heavy that it helps to keep the pool in the ground. But, if you drain your pool and the ground around it was to get a decent amount of water around it, it would absorb that water and swell. If the pool was empty it could actually be pushed up and out of the ground. Which
The other problem is that the plaster on your pool actually uses the water around it to help keep it moist and in good condition. After you leave it exposed to the open air for extended any extended period of time it will start to dry out. It will then start to crack, and pop up all over the pool.
So if you want to keep your pool in good condition (not to mention in the ground) then always make sure to keep the pool filled to the proper level. It may save a few dollars to not have a monthly service, but it could save you thousands in damages and repairs.