I think you must be referring to the fact that most universities require that you do the last 2 years worth of your degree at their institution? They will still let you transfer if you have more credits, but you won't be able to transfer all of your credits.
Internally it shouldn't matter, so long as the program accepts people who transfer into it (which would only apply in a very limited number of cases). If you transfer past 2nd year you are most likely going to need to take extra time to complete your degree though.
FAQ's:
1. Will I get in? See:
electronicinfo.ca for Ontario schools. If you have a couple percent above the marks there and it's not looking at supplementary, the answer is almost certainly yes.
2. Anything else: Google it before asking.
