DEAR MISS MANNERS: I enter the small waiting room of a professional whom I visit for professional services. As I open the door, its lower edge disturbs mail that is lying on the floor, having been delivered through a slot. I gently shift the mail with my foot to save it from being mangled by the door, and take a seat.
Would it be impolite (an intrusion) to gather the mail and put it on the nearby small shelf? Is it impolite (negligent of an ordinary courtesy) to leave the slightly mussed mail on the floor?
GENTLE READER: Yes, to your second quandary. It is not, as implied in your first, impolite to touch someone else's mail.
Touching, Miss Manners hastens to add, does not include shaking it and listening for the result, holding it up to a strong light source or sniffing it. Leaving someone else's possession in a place where it is likely to come to harm (such as the floor of a busy waiting room) is impolite, as is placing it somewhere where it will become lost (such as on a shelf intended for medical samples) or not readily visible.
Touching something with your shoe, gently or otherwise, is not always a show of disrespect (Miss Manners is thinking now of soccer), but she cannot think of any situation in which it displays respect.
Pick up the letters and give them to the next resident professional with whom you come into contact. Innocent as was the way in which you acquired the letters, it will still be best to explain the circumstances rather than leave the owner to jump to the wrong conclusion.