I have a friend who would like to visit Canada, however they have limited financial resources, therefore I would like to extend an invitation as a host. I am simply wondering if applying on the TRV as a financial supporter is a legally binding action. If any unexpected financial obligations arise, am I legally responsible for them?
There is no legal requirement for you to support them from an invitation. The approval of their application will have a strong bias on your friends own ability to pay for the trip.