The short answer to your question is yes.
If a school makes you an offer with, for example, an April 1st deadline, then a provisional acceptance will hold that spot for you after April 1st.
If you don't take another provisional acceptance at another Ontario school, and you don't withdraw your provisional acceptance with the school in question, then it will automatically become firm July 1st.
You can only provisionally accept one Ontario school at a time. If you've provisionally accepted one offer, and then receive another offer that you want to provisionally accept, you will lose the first offer as soon as you do.
You will also most likely have a tuition deposit deadline sometime in early June. If you don't pay that then you will also lose your provisional acceptance.
You should confirm all of this with both OLSAS and the individual schools though rather than taking my word for it.
Thank you for your reply!
They called right at 8 am, so I think they know they were the first call. I'm sure you're right though that it isn't a big deal in the grand scheme of things. I think I just needed some reassurance, lol.
Basically, if your understanding of the left is what the above posters believe, or if your understanding of the right is that they're all literally hitler, you probably want to leave politics out of anything. If you're capable of understanding even some nuance, then keep it in.
Law schools DGAF about your political affiliation. Most of law school was Big L and Big C.