Throwable creeper eggs do not work when thrown at walls/ceilings - more info

If you throw a throwable c-egg against a wall or ceiling, the creeper doesn't spawn and the egg is refunded to you. I assume this is meant to be a safeguard against glitch raiding but it seems overly strict - currently throwable c-eggs ONLY work if thrown at a floor. This is most of an issue for spawners. If a faction has spawner "pillars" that are connected to a ceiling, there's no way to destroy them with throwable c-eggs from below.