I think chainsaw safety is very important. I have a few logger buddies and every single one of them have either came close to getting injured or have gotten injured. These guys are professionals. If they can get hurt the guy that comes in off the street looking to buy one for the first time will sure to get hurt without a little guidance or a good talking to about safety using one.
If all you are charging is $5 for the dvd then as a dealer you are worried about people buying chainsaws and their safety give it to them with the purchace of the saw. If you are worried about the money charge and extra couple bucks for the saw. People wont know the difference and they will most likely watch it as they think it is free.
I have purchased many different types of equipement (lawn tractor, bush hog, mower, saw, and other that I cant think of right now) and most of them came with a dvd or vhs and safety videos.