A buddy and I were digging with small 6"x8" (blade) spades in a park a few years ago looking for colonial coinage The area was in a hay/weed field a farmer leased from the county. A park ranger walked up and said "someone called in saying someone was digging holes". The ranger saw that we were detecting, asked for permits and said "have a nice day fellows" then left.
One should use common sense as to when and where to use a spade or a hand digger. A sharp non toothed spade will absolutely dig a cleaner less destructive hole than a hand digger. Question; What's more important, how the grounds look, days after digging, or how it's perceived while in the act of digging? You and I know it's the former and the end result,.. but Joe public doesn't.
If you feel uncomfortable in an area with a shovel and eyes are upon you, that's your conscious telling you that a hand digger/tool is appropriate, the shovel should go back in the truck.
We do live in a world with other people, and should consider them, and hopefully, likewise.