We are renovating our pool and have a bit of a debate going on between the pool guy and the concrete guy. The pool has polymer sides and a vinyl liner. The pool guy wants the concrete deck poured so that concrete doesn't end up in the pool. He doesn't think the concrete guys are not neat enough. Concrete guy says liner and water goes in first because the added weight of the concrete may buckle the polymer sides.
I tend to agree with the concrete guy. We had a pool installed when I was a kid and the concrete deck was last.