Refuse een assignment because it 'cannot' be routed?

> the government (RIPE) 

RIPE is not a government.
RIPE sets policies based on consensus among its participants,
it does not make laws based on majority votes.

I do have sympathy with your problem, but I think a better way would be
to educate the ISP in question why the product you suggest would
increase their sales and improve customer satisfaction.

Another side of this coin is that the current policies puts a
strong emphasis on the use of dynamic IP addresses
for mass-market products.

-hph