This was my reply:
The way I was taught and the way I teach is for realism. Training at the park or next to a car is more likely to re-create a real life event. How about un-even ground? Rocks, ice, snow, hills, etc. Forget rolling on a forgiving pad in a dojo. Try rolling where there are pebbles, sticks, etc. Changes the dynamics of everything. There is a sense of security in a dojo. It's great for softness, great if you have a marketing campaign and are trying to emulate the Japanese dojo. Personally, I'm more concerned about preparing myself, family and friends for real life self-defense. I fight dirty and fight to win. I also train to run almost always. I've seen many Bujinkan practitioners and I tend to believe the majority would get there ass's handed to them by a street smart kid. I was lucky. My teacher was former Australian SAS. I was trained in Togakure Ryu as it was first introduced to the west. What I see in the Bujinkan dojos these days is soft. I love all the Buji people and have the highest respect for Soke Hatsumi. The art today seems to be focused on, well, the art. Not combat. I'm content with being outside the Bujinkan system even though that means I can never train with Soke because I don't pay my dues. Spend less time worrying about the finer details people and more on how to use something to defend yourself, family and friends. So for me a dojo is not necessary. I guess it's more of a personal choice and depends on your personal goals. Cheers all!
I don't think I have much more to add to that. Train on folks and have fun while doing it.