Mike, I don't know, again I'm only stating it in General terms that you need to be aware of what your signing. I thought the original NHRA "charter" was formed to try to get kids off the street back in the Post WW2 days, I wouldn't be surprised if there are still certain tenants that members are expected to uphold.
But I agree, if it doesn't specifically forbid it in their bylaws, then they (the NHRA) have absolutely no business meddling in the private 'off track' affairs of its members. I suspect they are really nervous about "bad publicity" backlash from the media that make no distinction between Drag Racing and Street Racing.