Dude,
If you spar NHB style with minimum safety gear, it would only make sense that the certain rules are set so you can get up and go to work the next day.
If you want to get "realistic training", then use the Fist Gear or Hi Gear and go at it. There is just adequate padding (especially on Hi Gear by Mr. Blauer) to increase your level of realism to the point where you are close or at the same intensity to a real fight. AND it will hurt as the padding in the latter suit is not adequate to absorb a ton of the shock... (you'd be surprised at how thin it is).
We use this method of training quite frequently and it's certainly an eye-opener. BUT, imho if you can't fight anyone off doing NHB/MMA type sparring then don't expect to win in an encounter going full on out.
Of course there are other aspects to a fight when you get into self-defense type training, but that's a whole another topic... (and it's been done to death in the regular KF forum).
I'd be curious to hear how you train "realistically"?
Later,
KG
P.S. I'll be out of town for the next couple of weeks and will have little or no access to the internet, so I may be late with my replies.