#1 There hasn't been a reported case of a bear attacking a human in the City of Toronto in quite some time. So, it would be hard for anyone in the city to convince a cop, or the court system, that they had a legitimate need for bear spray in the city.
#2 If you do carry dog spray, you would have to articulate, with a straight face, that you had a huge fear of dogs and that was the only reason you carried it. Perhaps a human attacked you, and you just happened to have the spray with you...... no problem using it then. But the moment you say that you carry it for use on humans it becomes a PROHIBITED (not restricted) weapon regardless of what the label reads.
#3 Pepper spray isn't effective on up to 20% of the population.
#4 Even if the pepper spray is effective, an attacker may be so focused on what he is doing that he will fight off the effects until after he has accomplished his goal, and you just have a more pissed off, vindictive attacker on your hands.
#5 Maybe the spray doesn't work on him, but it works great on you. You used it in a panic without the proper time and distance between you and the person attacking you, so you get contaminated. You just did all of his work for him.
The woman on this board, especially the SPs, are at a higher risk of being attacked than the general population. So, please don't let your only investment in your personal safety be a can of pepper spray.
Instead, educate yourself. There are great books like, "The Gift of Fear," by Gavin De Becker. There are always signs of violence long before it actually happens. If you can learn to pick up on them, you are more likely to avoid a violent confrontation entirely.
The good news is that women have excellent instincts for this sort of thing. The bad news is that all too often they don't trust their instincts, and end up getting attacked anyway. Many women who are attacked and/or sexually assaulted will say that something just didn't seem right with the situation beforehand... they sensed danger. However, for a variety of reasons, they chose to ignore those instincts.
As for protecting yourself from physical attacks, take a good self defense course. NOT martial arts, and NOT mixed martial arts. Take something that focuses on specific techniques you can use to inflict the maximum amount of pain you can to distract or disable an attacker long enough so that you can get to safety. There are a lot of really good courses tailored just for women.