I've been shopping for video transmitters,
and I've noticed that some of them require
amateur radio licences. This seems a little peculiar,
since as I understand it only non-commercial activities
are permitted under this license. Yet these devices
are clearly being used commercially. Is this requirement
usually ignored for use of these devices in practice? How
likely is the FCC (or the DOC in Canada, where I live) to
prosecute for use of these devices without a license?

Ian