I'm not doubting you, but what kind of picnic table?
In all the years I've been using portable grills I've even never scorched a table, let alone burned a hole in one. When I camp I have a couple of wooden cabinets that I made to transport and hold our kitchen stuff. They get put up on stands and then a 2' x 4? piece of plywood goes across the gap and the grill and stove go on top. The grill has never even scorched the plywood.