I’m certain at some point in time, Richtofen has used the summoning key just for shits and giggles. 

I can just imagine them all cleaning their clothes in a lake, bare naked. Then out plops the key from in between Edward’s ass cheeks, (because where else would it be) and he freezes them all in place. With their tootsie rolls and jawbreakers exposed for all to see, he just skips away, giggling.