Do not carry them on? So you recommend that they should be checked baggage instead? What does that accomplish besides making all of the inadvertently left on phones inaccessible to be turned off should they actually cause a problem?

Wouldn't it make more sense to say no cell phones on the plane?

P.S. Deltalina says cell phones should "remain off for the duration of the flight". Use of cell phones are not allowed from when the door is closed until the wheels hit the ground.