Mojo-trout, you bring up a good point that it's sometimes good to hunt at night (or ... at least .... in low traffic odd-ball times), NOT because a person thinks he's necessarily doing anything illegal, but simply to keep from having anyone assume that, or question that, or quizz you about whether you'll do harm, etc... Or to stop some busy-body from morphing something ELSE they *think* applies to your activity: usually the dreaded alteration and defacement junk (even though you know you'll leave no trace). So rather than even go down that road of semantics, I too hunt a lot at night. Because our hobby is an oddity, that draws stares and looks from passerbys, right? And our hobby has admitted connotations, right? So why swat hornet's nests? Why risk that someone will want to make a rule? Isn't out of site out-of-mind? Why do so many md'rs think that because it's not technically illegal at some particular place, that therefore they can go at high noon waltzing over people's beach blankets?
Detecting is a little like nose-picking: not necessarily "illegal", but for pete's sake, we all have a little discretion in our timing.
Don't use any headlamp or lights. Because otherwise, your eyes will become focused/adjusted to *just* that beam of light. And pretty soon, everything outside that beam will become blind. Instead, let your eyes become focussed on the regular star light, moon-light, etc... That's good enough to see where to swing your coil, walk, etc... And then you can have a tiny penlight stored in your apron to see the dates on coins or whatever.