First of all, where are the teachers in the classroom administering the tests? I think cheating is not that easy if teachers are paying attention while they administer tests.... Cheating has been around for ages before we had cell phones. Don't blame phones for students behavior.
More importantly teachers should re-evaluate their tests. If tests are really at high-level thinking requiring analysis, evaluation, synthesis, and application then they should be "cheat-proof." It is much easier to cheat on multiple choice or fill in the blank than on a test that actually requires thinking, interpreting, and students writing their own opinion.