i am thankful for the Gift of Discernment but in my understanding of it it is a continual judging Gift 24/7/365.
you can feel when someone is not Saved, when someone lying to you, when something is going to go badly,. it's a constant Spiritual Awareness. it's not saying to someone i saw you did this so you must be a sinner. it's a deep feeling that can make you feel uneasy or even ill like queasiness. but it is God Judging and you are aware of it.
Your comment about queasiness reminds me of an experience I had many years ago. A friend enjoyed collecting comic books as a hobby. I decided to tag along when they went in search of a specific edition. Wow. Were my "eyes" opened that day. As I trailed behind my friend I began feeling a slight feeling of queasiness. The further into the store we went the stronger the feeling got, when at last it began to effect my ability to breathe normally. It was at that point that revelation hit me like a cold bucket of water. Peering directly at me were "demonic fallen angels." There was depictions of them on comic book covers in every direction. I decided at that moment to leave the store and wait outside. The instant I exited the store my breathing returned to normal. It was at that point that I understood that demons/fallen angels were actually on the premises in the spiritual realm.
Many artists who do this kind of work undoubtedly think the ideas are the result of creative juices flowing from no where other than themselves. They are wrong. And no doubt would be shocked to realize their thoughts are being manipulated by the enemy. Satan and his crew want God's intended children to idolize them rather than the God that loved and died to save them. They draw the least suspecting into their web of deceit in ways many do not understand in an effort to take as many with them into the pits of hell because of their hatred for God.
It is through the gifts of the Spirit that God reveals many of the tactics of the enemy. And that is why, as you said, that the enemy fights so hard against the truth that spiritual gifts are still in operation today. The more people he keeps blind the more damage he can instill in them, and also limit them from helping those they love. I for one, as the story conveys, did not understand the connection between actual fallen angels and their influence in the case of comic books. It was only after experiencing the gift of discerning spirits that my eyes were open that day. Most often, opening doors to the spiritual realm happens through seemingly "innocent" ways.
I believe wholeheartedly that many have been, and will continue to be drawn back from the brink of hell through the gifts of the Spirit that God so graciously gave to the church for that exact purpose.