i'm not a fan of random O/B. A well-designed hole should incorporate O/B in a purposeful and deliberate manner.
The use of O/B should be reserved for errant shots or for landing areas that a designer wants to define as O/B because they are attempting to force a certain risk vs reward decision, or alternatively because the designer wants to force a specific kind of shot or play on the hole.
If you were to define your picnic table area directly on a line with the fairway and the pin as O/B it should only be done if it forces a player to decide if they should lay up short of the area or attempt to throw over it. An area 15' x 15" is so small that one cannot predict with any great degree of certainty if landing in that area is a result of randomness or a bad throw so it doesnt seem to fit into the risk vs reward arena.
I'd therefore conclude it should be a bunCR.