If you watch shows through their set top box it doesn't count towards any limit. So, kind of like standard cable going to a TV, where the TV channels are on a dedicated 'connection' to the provider and watching TV doesn't utilize the broadband connection.
I'd like to know if their set top box utilizes the same pipe and throughput going to your house, and if watching a show through their set top box would diminish throughput speeds for others on the line. If it does, then that's bogus. If their box utilizes a separate dedicated connection to Shaw, then that's fine and I say fair.
However, in practice, it's hard for average folks to understand why Shaw's box doesn't count towards a limit when the Apple TV, Netflix-enabled Blu-ray box or whatever DOES count towards the limit. But I'm not sure Shaw is in the wrong here if their box has a dedicated 'line' to them.