The question of legality regarding shining lights in fields depends on the particular jurisdiction (state or country) in which you live. The best thing to do is contact your local Fish, Game or Wildlife agency to learn the rules that affect you. These laws are usually published on the web. In some places it's perfectly legal, in some places allowed under limited circumstances and in others not allowed at all.
The practice is known variously as
jacklighting,
spotlighting or lamping and even in places where it is not illegal it is generally frowned upon by wildlife specialists.
Here in Vermont where I live it is illegal to shine a light in a field for
any reason regardless of whether you have a weapon with you or if you are aiming your light at an animal. Saying, I'm a "flashaholic" wouldn't cut it with the game warden. The law reads:
"It is illegal to intentionally throw or cast the rays of a spotlight, jack, or other artificial light on any highway, or any field, woodland or forest, in order to spot, locate, take, or attempt to spot, locate or take any wild animal."
There has been an ongoing problem in certain states with jacking deer at night so I guess the idea behind such a strict law is so there is no question about what you are doing with your flashlight out there at night. Although I am a hunter I respect the game laws but I really didn't get what the law was all about until a couple of idiots decided to try to jack deer on my property at 2 o'clock in the morning. I happened to be awake and saw a very bright light sweep across my field and heard a firearm discharge from the road right near my house! These guys were even stupid enough to come back the next day to see if they hit anything, so I was able to report them.