[steaknsteak]

Football players purposely spear other players with their helmets with full force. They had to make rules against doing this, and it still happens, although with less frequency. They are not using their helmets as a last line of defense like your motorcycle helmet. They use them as weapons.

[Accipitriform]

It's not happening much at all in NFL football, since it's a major penalty if caught, and it's hard to hide.

I do hope helmet technology improves to handle inadvertent contact.

[melq]

Disagree, it happens all the time. Its a 'major penalty' in that you get fined many thousands of dollars, but I'm pretty sure the team pays it anyway, and that is a drop in the bucket.

http://bleacherreport.com/articles/2757235-rob-gronkowski-sa...

And furthermore, in that article Gronkowski is quoted as even preferring to take dangerous hits in the head like that, instead of risking re-injuring a bad knee. Not a great policy.

[switchbak]

This is exactly true. Technically there are rules against it, but this happens on essentially every play.