Its your aunts Property. How long has the other hunter use the land, years of no abuse its hard to say he has done your aunt wrong. I have got permission to hunt property of my friends and found that other are also using the land. I have made my friends aware of this and they said they would talk with the other hunter on hunting with friends.
Fine out what she let the other hunter do. If she cant remember (because of her age) ask her what SHE would like of you to do with the property.This might a time to sit back and see what the other guys does for a year.

Not sure of your age and size of land.( I say age because its harder for a young hunter to police land ) . Maybe let the other hunter know you will be out there this year but not when and where,but you let him know if you plan to gun hunt.Have him meet with you and your aunt (an/or parents) so everyone is on the same page. A face to face can go a say a lot.

Here in Va you have to have a sign paper to hunt posted land.
I hunt land that any day can be taken away be a family member, I treat the land owner with respect and stop by and spend some time talking with them has much has I think I would want to be bother with if it was my land.