There are quite a few flavors of libertarian. Although some would not support such a bill, others would. I'm a libertarian in that adults should be allowed to do as they please without government intervention as long as they do not hurt others. For example, I don't think the government should regulate romantic relationships - letting some get married, but not others. But when it comes to commercial transactions, protecting the environment, and protecting the rights of queers in their workplaces, I would not call myself a libertarian.