It would give all of the ever so lonely and horny men and woman further incentive to get together and fuck because they can't just do it alone. But even with immense waves of pussy, no man could ever do without giving it to himself every once and a while (I mean everyday) so they would still be at a loss. Moral of the story, more fucking, but overall, less getting it.
My solution to said law/ what could naturally happen is the market for shit like the fleshlight and all that weird fake stuff would sky rocket. People would come up with a new official term for beating the meat, saying straight up using your hand is "masturbating" but if your doing it with something else, technically you aren't doing it..
Either way, if the tens of millions of guys around the country can hide it from the people that are living in the same household (every teenage boy), I don't think it would be too hard for guys in general to hide it from police...