That's the thing, it wasn't physical contact that activated the spell,it was apparently that it had been activated by the paladins reading the rune on the tiny bouncing ball. Heck it would have been a lot more effective just to have the rune on a piece of paper and hold it up. Same effect. It was also bizarre that so many paladins lost their will saves, but at least that could be explained by some of them being low level.