Steel roofs ridge vents

Is there any concerns with with some steel roof installations cutting a hole along the ridge of roof line and what they cover it with to elminate pests and insects as well water.

I realize it is designed for air exchange between the layers if strapped. Some companies strap but do not see the need to cut out at the roof ridge.

What is the best cover for a cut out roof ridge and vent?

There does not seem to be any consistancy with this product and installers?

I do not mind cutting the ridge area but I am not overly impressed with what they are covering it with such as a foam strip. What else should be applied. Foam strips deteriorate under hot conditions.

No one can seem to give a straight logical scientific answer and this part of the industry needs some standards.

http://www.homerestorationsmd.com/md-roof-repair-potomac-egan-3.JPG

http://www.bestbuymetals.com/store/images/product-profile-vent.png