"Whom are" or "For whom are?"

I was asked to create a layout for a bulletin board that is primarily family related and casual. It is brightly colored and will be used to post photos and personal remarks relating to safety. The main text was to read, "Who are you safe for?" I'm aware that this syntax is now considered acceptable for very relaxed situations, however I chose to use "Whom are you safe for?" as I felt it was the most appropriate and balanced choice given the informal yet reflective purpose of the bulletin board. I am aware that "For whom are you safe?" would also be a perfectly acceptable choice in terms of proper syntax, but it feels terribly pedantic given the situation. I do not wish to sound stuffy or pretentious; it would not be appropriate considering the audience. I would appreciate discussion of what might be the best syntax for this phrase considering the project at
hand. Thank you!