"Edmonton's new bylaws (as of last summer) forbid the posession of any animal (and their offspring/young) whose adult form typically exceeds 10kg.....this effectively makes boas, blood pythons, and large tortoises illegal in Edmonton, although I am sure that it was not intended to do so when it was written."
As much as that weight is a little low and covers many "harmless" species, I think bans on things accourding to weights is a MUCH better idea than outright bans, etc. I think if you are willing to own an animal like a retic, burm or giant tortoise then you should also be willing to research to make sure your location is acceptable in the law and if not, move. The responsibility of these large creatures is something 100% different than most snakes, and the owners should be 100% different from average small species keepers. It's far better like that then just banning all pythons, boas, etc.