I think that might be true on the Tahoe or some other models, but on the Yukon it's clips and pinscrews that are not easily accessible from the top.I second @Jetskier77. What is the purpose of the question?
The lower valance, or air dam, is to deflect air around the vehicle for better MPG. Removing it should be easy - they are all push pins and quick nuts. Cutting will require some skill, but again....why?
Is there a group that judges vehicles based off their ground clearance to air dam ratio I'm not aware of?