I've came across 2 types of poachers in the past on my family's land back in eastern TN, little over 1500 acres of small mountains. Most of the time the moment you catch them on your land they take off running to get out of there and avoid you. Then there are those that think they are doing no wrong and they have every right to be there.
I came across 2 guys on my grandfathers land (where he taught me how to hunt for seng) while digging one day, told them it was private property and they had no right to be there. They informed me that they had gotten permission from someone I had never heard of that they said owned all the land around there. I quickly informed them of the actual owner and told them to either leave or we could go see my grandfather together and they could ask him thierselves. Keep in mind, at this time I was only 23 and both these men were around 40 and double my size. They still thought they were in the right and one decided to pull out his bowie knife and started digging dirt out from under his nails while stating that they had a right to be there and was not leaving and there was nothing I was going to do about it. A little scared/intimidated and outnumbered, not to mention about 2 miles into the woods and at least 30 minutes from any type of law enforcement, I pulled out my 45 and pointed right at his head. I wish I could have gotten a picture of they guys face, his buddy took off so quick he fell about 10 times trying to get off the mountain. I ended up following them out and calling the cops and my grandpa.
Sadly enough, gramps pressed charges, think they got $500 fine each and some community service each. It wasn't maybe a month later my grandpa and one of my uncles caught the same 2 guys deer hunting out of one of our tree stands. To my understanding I reckon my gramps pulled them out of the stand an gave them a whooping of a lifetime, or so the story goes, to this day ain't seen them back there again.
Long story short, I think to properly keep a caught poacher from coming back you need to put the fear of God into them or they will just come back the next day.