this is what is happening now on our air ports as well. we have to be careful about such attache cases.better we have such where there is no Zip but other locking systems. now a days one has to be aware of immigration people. what they do is just snatch a page out of ur pasport when u land and keep the record of ur return date and other particular dates. when u r there to depart that is the time when they will open ur pasport ant ask u about the missing page and threat u for prosecution or stop u boarding the plane and will charge u heavy amount as bribe. so never remove ur eyes when ur passport is with them they may divert ur attention by some excuse and do their act so u must check each page by number when they give it back to u.