I feel like your staffer should have noticed what you were doing; every time I've done one of these, the staffers were usually fairly attentive, and would guide us away from the inadvertent red herrings like this.
I agree you need a hands on approach to guiding. For example, in the same game we found a pencil but the lead was broken. So we asked "is the lead supposed to be broken; if not I have a pen in my pocket..." and they gave an emphatic "yes it's part of the challenge". So when other obstacles came up we of course assumed they were part of the challenge too.