In the world of freedom vs felony. Most will want to keep their freedom.
Full auto (without gov permission) is a felony just like an unregistered 80% if this law passes.
Would you take an "illegal" full auto rifle to the range and use it openly? If the answer is no the I don't see why you'd bring out an 80% you built as either one catches you a felony unless you can vouch for 100% of the people at that range and the staff and you know that a Le officer isn't there.
Makes its hard to train with the 80% lowers at most ranges don't ya think? As I said it may not be very likely on a grand scale but smaller jurisdictions and states may be able to pull off some sort of enforcement
Regardless, it's a sign of things to come and more incrementalism