Wonder where she got the 500m from and why it would matter. She shouldn't have a problem getting 1000 signatures, just ring a Conservative supporter's doorbell.
It's not like pot will be sold out in the open, nor do I know of any LCBO within a 500m radius to begin with. Just another person who has the mentality that pot is the worst thing a person can possibly do - In Stephen Harper's words, "infinitely worse than tobacco".
http://www.cbc.ca/news/politics/stephen-harper-pot-marijuana-1.3255727
Like you mentioned Boots, in the 2 high schools I've been to, there has been a convenience store within walking distance that doesn't ID for cigarettes even though it is painfully obvious that the person is under 18. I have never smoked a cigarette myself and I knew this.
Pot was being circulated by the groups that we're trying to phase out by legalization. By creating that boundary, it keeps the 'black market' alive and likely charging a higher premium of what they sell it at now in the same place. Most of the people I knew that smoked pot in school primarily got it from people that attend the school.
Just because people have access to certain drugs, doesn't mean that they're going to do it. I had access to cigarettes, pot, and alcohol since I was 13 yet never smoked a cigarette, didn't smoke pot until I was 20, and only drank alcohol occasionally when I was 19. I find that putting all these barriers further draw the curiosity of young people which would be better off educating them in school of the effects of these drugs rather than the whole scare tactic of "These are drugs, if you do them, you will be addicted and die a horrible death" from grade school. After all, in grade 6, I was taught that pot, cocaine, and heroin "were bad" and no further explanation of the drugs were explained through school. They didn't even touch on the topic of cigarettes and alcohol.
Had I not done my own research, I would have seen pot at the same level as cocaine and heroin. I would then see someone else smoking pot regularly and see that they're okay. Then that would mean that they're probably lying about cocaine and heroin right? Everybody smokes cigarettes and drinks alcohol and seem okay too!