If there is a specific behavior that is dangerous to others, or the economy or whatever, just punish that behavior.
That would work with normal people. The problem with psychopaths is that they are not afraid and not deterred by the punishment. From wikipedia (emphasis mine):
Psychopathy is a personality disorder that has been variously described as characterized by shallow emotions (in particular reduced fear), stress tolerance, lacking empathy, coldheartedness, egocentricity, superficial charm, manipulativeness, irresponsibility, impulsivity, criminality, antisocial behaviors such as lacking guilt and living a parasitic lifestyle.
Besides there already are some waterproof and water resistant smartphones, like sony xperia go and panasonic eluga.
tl;dr: I wouldn't trust them.
"Consistency requires you to be as ignorant today as you were a year ago." -- Bernard Berenson