Well there ARE FCC restrictions on what frequencies you're allowed to transmit on. Most frequencies are "owned" by someone that has the right to transmit cell phone, radio, television, or other data across them. You may recall, for example, that there was a big bidding war several years ago when some of the old UHF bands were sold off. There are some open frequencies which you're allowed to broadcast without a license on, these are the ones that your cordless house phone and such will transmit on. Whether or not this is a legitimate reason for the closed source antenna code is beyond my scope of knowledge.