I've seen this before, this indeed is spoofing. There are some CLEC's and ILEC's out there who do not monitor the spoofing going on. A few providers I know of do. ModernWorks is one that does not allow it, as doesn't Fibrenetics. Bell doesn't care as they mostly have resellers like Distributel to handle stuff like that.
The CRTC knows this is happening and they don't really care. It takes too much resources to stop it. There was a Marketplace 2 part series on this(mostly concerning Duct Cleaning Services)that are spoofing the numbers from Pakistan and India.