Don, consider this too, you did the right things when the accident occurred. You had slit seconds to make choices about maneuvering, braking, staying on the throttle and more, and you did the right things to stay up and in control. If you should encounter deer again, you will again make the right decisions and come out as well as possible. It's simply part of your riding reflexes or you wouldn't have come out so well this time. All you have done is proven in the real world that the knowledge and training you have is solid and in a crunch, you do the right things.
We manage our risks. That includes choosing to take the car on occasion too. Assess at each trip plan and choose what feels right for you then, rather than attempting to form a blanket decision now about all future rides or events. We do this to have fun. If you can't ride with Seth and have fun, don't. But don't let some apprehension stop you either, some things have to be worked through in order to get over the hump, so to speak.
You might consider a full face helmet or some modulars for Seth as one step to up the preventative protection. Perhaps some armored riding pants as well. Hip & knee armor help a lot in a get off.
Regardless, Ty and Shiny are right, it doesn't matter how you show up to an event, we still like you. It's about the friendships we make, not how we get to the events. We do enjoy riding, but you won't be told to go away if you drive. (We'll just make you last in the group rides!)