If students cheat they hurt only themselves. Make sure they understand the consequences for cheating (missing out on learning) and that's about all you can do.
Former (second-generation) college professor, here. I find it almost impossible to be cynical enough about the US education industry.
This statement is more defensible after removing “only”. If it “only” hurt the cheaters, there would be no need to police cheating at all.
And they'll do it with all the 'unnecessarily high stakes' and 'risk of unconscious bias' and 'not truly representative' problems that written exams have; and a bunch of extra problems too.