Using a Chastity Cage

I see a lot of videos where a sub is wearing a chastity cage, and I can't help but think that the dom missed an opportunity.

Pulling the penis into the cage by the foreskin may make it easier to get on, but it covers the glans. If the sensitive glans is exposed, teasing is more effective.

I'd also like to see cages that have the frenulum exposed, again to increase the effectiveness of teasing.