If you "See" a collision on your end, then you get dmg.
If your opponent didn't "See" it on their end, they didn't get dmg. It's a near miss to them.
I bet that some times when you "See" a near miss, your opponent "Saw" a collision and took damage. You didn't take damge because you didn't "see" the collision. Ever get a "xxx" has collided with you msg but not taken any dmg?
Basically if you see it, you get damage. But what you see as a near miss, might register as a ram on THEIR front end, and they took dmg.
(and yes, please do a search, this horse is long dead and beaten)