This has been a fascinating discussion. I did some digging and found this on USCIS website.
Advance Parole
Most aliens who have pending applications for immigration benefits or for changes in nonimmigrant status need Advance Parole to re-enter the U.S. after traveling abroad. Aliens applying for advance parole on the basis of a pending application for adjustment of status must be approved for advance parole prior to leaving the United States in order to avoid the termination of their pending application for adjustment. Note: this does not apply to aliens who have applied to adjust to permanent resident status and who maintain H-1B (Specialty Worker) or L-1 (Intracompany Transferee) status, or their dependents, who have applied to adjust to permanent resident status and who have valid H-1B or L status and valid visas, V nonimmigrants who have a valid V nonimmigrant visa, are in valid V nonimmigrant status and have or obtain a valid V nonimmigrant visa before applying for readmission to the US, and K-3/4 nonimmigrants who have applied to adjust to permanent resident status and who have a valid K-3/4 nonimmigrant visa, are in valid K-3/4 nonimmigrant status and have or obtain a valid K-3/4 nonimmigrant visa before applying for readmission to the US.
Clearly, it means that your 485 does get terminated if you travel w/o AP unless you are on H1/L1 or other exemptions, notwithstanding somebody falling "through the cracks". If you read closely, your 485 get terminated as soon as you LEAVE US, it has nothing to do with how you subsequently reenter. I was under the impression that AP is simply to be used for applying for entry, but I stand corrected.
