There are several old threads that state that Europeans takes the test in the afternoon of test day, so they are effectively writing at the same time as east coast writers. It also states that in other parts of the world like Asia, the test is written the following day in the morning, so they can, in fact, check the Internet for test details.
We all apparently are given the same test, except for Sabbath writers.
I'm sure the LSAC is aware of the time difference and the potential for cheating. They are also experts at analyzing their own data. I can only assume that since Asia is not given a different test, they have analyzed the performance of writers in Asia and determined that their performance is not statistically different enough from North American writers to make their test different.
Do a search and you'll find some old threads on the subject.