Ditto El Conejo's comment about the polite handling of other people's guns. I DO hold the top lever and ease it down gently, when handling someone else's gun, so as not to offend the owner. Doing that in the field or on the range is the mark of one who thinks he is doing something beneficial for his gun(mistakenly, IMO). Often the "lever sneakers" follow up this unnecessary ritual by forcing the lever to the left after closing, to be sure it's locked, probably negating any load saving imagined by holding it, in the first place. Along with all the makers' advice, I have seen, on TV, a gunsmith/gunmaker at Purdey's closing a fine, one of a kind, 100+ year old Purdey SxS in the normal manner, intended for snaplock guns(thumb OFF the top lever)
