Has anyone figured out what the purpose of the clear plastic "sure-nail" nailing strip is? It lines up with the tar strip when the shingles are layed. It seems to me that this strip would interfer with the tar strip. The tar strip bonds nicely with this plastic strip, but what happens if this strips comes loose? I've called OC twice about this and got the same person both times...he just reads a script and knows less than I do about the shingles. Otherwise, they seem like a good shingle...great sealant...bonds in minutes to everthing including felt, shoes, pants, hoses, loose wrappers, ect.