Want to make it harder for kids to cheat? Try assessing in a more meaningful way. Multiple choice tests that can be passed by tapping an answer to a friend should be tossed. It's no different than kids using a phone to cheat on a test. If the phone can provide the simple answer, there is something wrong with the test, not the phone.
Look at more project based learning assessments and presentations in class. Have students demonstrate understanding beyond the recalling of memorized then forgotten facts. Get them out of their seat and show everyone what they know.
If students are more engaged and are showing what they have learned, the fear of the Apple Watch or whatever tool comes along will be a thing of the past.