It's never a good idea to stand on your pool table, for multiple reasons. Chief among them is the leveling: your pool table surface is built with three separate pieces of slate, joined together with wax and painstakingly leveled by your billiard mechanic. The localized pressure of a person standing on the table will almost certainly separate the underlying slate section from the rest, and require a service call to re-level, and possibly even require cloth removal to fix.