I find it wierd that a farmer would offer the option? Normal routine is, you get your harvest in soon as it's ready, because otherwise you stand chance of losing some or all of it due to factors such as the weather knocking the dead stalks down, getting too wet and not being able to get the combine in, etc.
Is this just a small food plot or something like that? If so, leave it stand.
Hunting in and around corn fields is a way of life in the midwest, you just deal with it. Corn fields are great security cover for deer, because it's near impossible for someone to slip up on them undetected in the corn, and they are well hidden from view.
They are picking corn like mad already around here, and bow season doesn't even start until 10/1. Most of the corn will be out of the fields in a few weeks, before most of the serious hunting gets going.
I like to hunt in and around standing corn because the deer seem to be at ease and feel secure. They move about more freely. A hot set up us a tree stand in a fence row through or alongside the standing corn, or a woods edge adjacent standing corn. In early season, deer frequently bed in the standing corn, then migrate into the timber in the evenings to feed on fallen acorns.
It's not much of a food magnet factor around here because it is everywhere. The deer really don't start hitting the corn hard for feed until it gets real cold and a little snow cover. Then they need the carbs to stay warm, and you'll see bunches of them feeding in the afternoons and evenings in harvested corn fields that have some waste grain scattered in them.
Now if this place has the only corn in a big area, you might have a real magnet to draw them in with. Not knowing any more about the conditions, that's about all I can add. Now if you want some real corn field hunting experience sometime, come to my neck of the woods. We're lucky to have 50 acres of woods and cover in every square mile and the rest is all corn and soybeans. Trees are pretty scarce in some areas. It's different hunting, but we've got nice whitetails, and lots of them.