Just my experience as a hunter and gardener--
Deer seem to like to "take thy easy route" when ever possible. If the gate to the garden is open I personally say they will walk right on in over jumping in. I have a 5 foot fence with a 7 foot gate opening for the tractor to (barely) fit threw. I have seen deer walk in the open gate, but jump out over the fence when startled.
At the end of the day tho, they are wild animals and there is no way to predict what they will do, but a fence will maybe act as a deterrence for them. Someone I know sprayed their garden fence with the organic deer repellent stuff , set up a trail camera and haven't had one deer jump over they fence. Fence or repellent? Im sure a fence wouldn't hurt
"Optimism is a good characteristic, but if carried to an excess, it becomes foolishness. We are prone to speak of the resources of this country as inexhaustible; this is not so."
â€• Theodore Roosevelt