I'd vote with the hood tie down ropes possibly entangling the deer, especially if you have to 2 and criss-cross them to form an X. If the ropes were strong enough to take the initial hit, the deer might just be repelled off and your car/canoe would suffer minor damage.

In MI, you hit a deer and kill it, the carcass is yours. I know people who have hit and killed one, gut it out and took it to nearest butcher shop for processing. Takes some of the sting out of paying your deductible.

On serious note, when I was a test driver for GM, I worked the mid-night shift and Milford Proving ground.
Even though the facility was surrounded by a high wire fence, the deer managed to find their way onto the grounds and it was always a concern.

They brought in safety experts to talk to the drivers about what to do if a deer collision is imminent and you have time for some reaction?
Never swerve hard or try and run off road to avoid deer. Both cases can cause you to lose control, maybe roll over or hit obstacle head on. Deer "might" be missed but you are dead/injured or trying to explain to insurance company that it was a deer, not you falling asleep or inattentiveness that caused the accident.

DO brake firmly without losing control, that's when those anti-lock brakes really shine. Try and hit the critter in the front/rear quarters which hopefully will send them spinning off to side.
Of course if you hit them mid leap, and they miss those ropes your screwed when it comes crashing thru the windshield.

My Dad was friends with an old time constable that lived in Northern Lower MI. He told the story of finding a car stopped dead in the road late at night with screams and some kid of commotion going on in back seat.
He cautiously approached the vehicle thinking it was some kind of assault going on?

Turns out a big spike horn had jumped in front of car, went thru windshield, hit the guy in the chest and broke the bench front seat. The guys leg had hit the gear shift putting it into park.
When the old timer opened the rear doors, the guy had the deer by the horns, screaming bloody murder, covered in his own blood as the spike was tearing him up with all 4 hoofs going at once.

The constable feared shooting the guy accidentally, but eventually he got one hand on a spike and pulled the head back far enough so he could shoot it point blank in the head.
The guy was a local and survived without any major injuries except he had a chest covered in scars that resembled deer hoofs.
He was so shaken by the incident that he never drove at night again!

I don't even want to think about hitting a moose. One year saw a moose/car accident on way to Thunder Bay.
Little car, big moose. Moose was still alive, laying across the front seat area. Troopers shot the moose.
Two people in front seat were killed/decapitated when moose sheared of roof of car.

Same advice for moose as deer, except if you survive or come out un-hurt, your vehicle won't be going anywhere for awhile, if at all.

Dude, slowing down to 30 on rural roads is a particularly bad idea, deer or no deer........a case where the cure is worse than the disease........do the math with someone doing 70, throw in a phone call, a text or digging for a CD and the potential for a strike from another car is higher than you might think (yes I understand it wouldn't be your fault......tell it to the undertaker).